High Voltage
·
2024
·
IF 4.4
Yunxiao Zhang,Wenxin Lin,Yuanxiang Zhou,Weiwei Xing,Jiayu Cheng,Chenyuan Teng
Electrical tree degradation is one of the main causes of insulation failure in high-frequency transformers. Electrical tree degradation is studied on pure epoxy resin (EP) and MgO/EP composites at frequencies ranging from 50 Hz to 130 kHz. The results show that the tree initiation voltage of EP decreases, while the growth rate and the expansion coefficient increase with frequency. Moreover, the bubble phenomenon at high frequencies in EP composites is discussed. Combined with trap distribution characteristics within the material, the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is discussed. It can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks, which can improve the electrical tree resistance performance of EP composites in a wide frequency range.
研究领域:
电气工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MEASUREMENT SCIENCE and TECHNOLOGY
·
2014
·Vol. 25
·期 8
·085105
·
IF 1.352
Yixin Chu,Qianchun Zhang,Wanqin Zhang,Guoyi Zhang,Shouli Zhu
A gaseous sensor was developed for the determination of dimethyl ether (DME) on the basis of its cataluminescence (CTL) emission on the surface of MgO/In2O3 composite (mass ratio = 1:2). The sensor exhibited high sensitivity and selectivity to DME at a temperature of 245 °C. Under the optimized experimental conditions, the linear range of CTL intensity versus DME concentration was 50–12 000 ppm with a limit of detection of 14 ppm (signal to noise (S/N) = 3). By selecting the appropriate ratio of MgO to In2O3 and the detecting wavelength, the CTL intensities of ether and ethanol could be reduced to 7.3% and 3.9% compared with that of DME. For other compounds, including carbon tetrachloride, formaldehyde, dimethyl sulfate and methyl acetate, etc, no emissions or only very weak ones were detected. The sensor was applied to analyze samples spiked with known concentrations of DME. The concentrations of DME in all samples were well quantified with satisfactory recoveries.
研究领域:
分析化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2014
·Vol. 111
·期 2
·633-645
·
IF 0.983
Yue Chuan-Jun,Gu Li-Ping,Su Yang,Zhu Shao-Ping
Cu/MgO and MgO nested on the surface of Raney Cu were prepared by a wet-mixing method and used as catalyst for glycerol hydrogenolysis. The texture of Raney Cu/MgO was characterized by X-ray diffraction and transmission electron microscopy, Brunauer–Emmett–Teller, and CO 2 -temperature-programmed desorption techniques. Results indicated that MgO was well dispersed in the pores of Raney Cu. Moreover, Raney Cu with large specific surface area had a larger contact surface for MgO, and a new phase of Cu–MgO was produced. Glycerol hydrogenolysis was selectively catalyzed under the synergistic effect of Cu and MgO in Cu/MgO catalyst. Under the moderate conditions of 180 °C and 1 MPa H 2 , the conversion of glycerol was 36.2 wt% and the selectivity for 1,2-propanediol was ~85 wt% when chemical equilibrium.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Na Zhang,Anxin Liu,Ling Chen,Xiangyu Xue,Hongfa Yu,Mingfang Ba
This study systematically investigated the hydration process and phase evolution of MgO-MgSO₄-H₂O (M-M-H) systems with and without chemical additive at different hydration stages using X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), hydration heat measurement, and microstructural characterization. The results demonstrate that the formation of magnesium oxysulfate cement (MOSc) product phases is intrinsically governed by Mg²⁺ concentration in the liquid phase, which is co-regulated by both raw material molar ratios and phase regions. At low Mg²⁺ concentrations, the primary hydration products in chemical additive-free MOSc are 3Mg(OH)₂·MgSO₄·8H₂O (3–1–8 phase) and Mg(OH)₂. When Mg²⁺ concentration reaches a critical threshold, 5Mg(OH)₂·MgSO₄·7H₂O (5–1–7 phase) additionally forms in the system. Chemical additive significantly alter the hydration process by enhancing Mg²⁺ concentration and promoting MgO particle participation, ultimately shifting the dominant product phases to 5–1–7 and Mg(OH)₂. These findings provide deeper mechanistic understanding of hydration reactions in M-M-H systems and offer important guidelines for research and applications of chemically modified MOSc.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Yunjie Dong,Zhoufu Wang,Yan Ma,Hao Liu,Chengji Deng,Zhongfeng Xia,Zhenghuang Quan,Xitang Wang,Ling Zhang
The mechanism of the additive La 2 O 3 on the sintering process of MgO-CaO ceramics was investigated by molecular dynamics simulation, and the interfacial reaction and nanoparticles sintering models were established. The simulations demonstrated that MgO and CaO dissolve into La 2 O 3 crystals, creating O 2- vacancies around Mg 2+ and Ca 2+ . These vacancies significantly increase the diffusion rate of ions. Meanwhile, the La 2 O 3 shifts the sintering driving force from reducing internal energy to increasing entropy, thereby enhancing the sintering degree of nanoparticles. However, excessive La 2 O 3 introduction prolongs solid solution reaction times and impedes particle-particle contact, negatively affecting sintering densification. Experimental results show that the density of MgO-CaO ceramics initially increases with the addition of La 2 O 3 , reaching a peak of 3.43 g/cm³ at 0.3 mol%, before decreasing. This result aligns with the model's predictions regarding the effect of La 2 O 3 addition. Moreover, the established models offer reference for selecting sintering aids in composite ceramics production.
研究领域:
材料科学
·
计算模拟
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2016
·
IF 2.75
Yi Li,Muhammad Nadeem Amin,Xingmei Lu,Chunshan Li,Fuqiang Ren,Suojiang Zhang
The catalyst NiO/MgO–Al 2 O 3 was prepared by loading magnesium and nickel onto the surface of γ-Al 2 O 3 beads, respectively, and was adapted to in situ upgrade the high temperature pyrolysis vapor derived from coal pyrolysis. The catalyst synthesis process, and structural variation were characterized by the XRD, SEM, and physical adsorption analyzer. In order to examine the catalytic effect on the different nickel loading ratio in the catalysts, the solid–liquid–gas product distribution, variation of gas and components of coal tar were studied by simulated distillation, GC/MS, elemental analysis and so on. The results shows both the tar yield and the content of the light fraction in the tar can be increased by catalytic up grade. The catalyst has a strong ability to convert the heavy component and polycyclic aromatic hydrocarbons in the tar to lower molecular weight components.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Xingye Zeng,Cunhui Lin,Qinggang Ren,Shufeng Shan,Hanlu Wang
Developing a highly efficient catalyst is one of the important topics in the field of oxidative desulfurization from liquid fuels. In this study, the composite metal oxide catalysts (CuO-MgO) with co-catalyst MgMoO 4 were prepared by co-precipitation method with simple process, high efficiency and good performance and their structures characterized. An efficient extractive catalytic oxidative desulfurization (ECODS) system for liquid fuel was successfully developed on the basis of as-prepared CuO-MgO-MgMoO 4 (CuMgMo) as the catalyst, sodium hypochlorite (NaClO) as the oxidant, and acetonitrile as the extractant. Taking the n -decane and n -tetradecane containing dibenzothiophene (DBT) as the test model oil sample, the main parameters influencing desulfurization performance were examined in detail, such as the molybdenum content, the dosage of CuMgMo, the reaction temperature, the initial S-concentration, the different extractants, the volume ratio of extractant to oil, the different oxidants, and the molar ratio of NaClO to DBT . Based on optimized desulfurization reaction conditions, the model oil containing different sulfur compounds (benzothiophene, 4-methyldibenzothiophene, and 4,6-dimethyldibenzothiophene) and the real oil (straight-run gasoline, straight-run kerosene, and straight-run diesel) were further tested. Based on the free radical trapping experiments and the calculation of density functional theory, the reaction mechanism was deeply explored. The results showed that the de-electron reaction of DBT was mainly catalyzed by MgMoO 4 and the reaction of HClO obtaining electron was mainly catalyzed by CuO. MgMoO 4 plays an assisting role in improving the catalytic reaction rate. This work will provide a useful reference for the construction of efficient ECODS system using composite metal oxides.
研究领域:
化学工程
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Jiangmin Song,Guanxing Huang,Dongya Han,Qinxuan Hou,Ruinan Liu
High performance and high permeability of reactive materials are crucial issues for the remedy of arsenic (As)-enriched groundwater by permeable reactive barriers. The remediation strategy integrating adsorption and oxidation has gained wide concerns due to its deep removal for As(Ⅲ). In this study, a granular bifunctional nanocomposite MgO-Chitosan-MnO 2 (MgO-CS-MnO 2 ) was fabricated as permeable reactive media for the in-situ remediation for high As groundwater. The needle structure of MnO 2 could provide adequate oxidation sites, furthermore, the multilayer porous characteristic of MgO-CS could also meet higher adsorption capacity. As a result, the estimated maximal adsorption capacity of MgO-CS-MnO 2 for As(Ⅲ) reached to 266.61 mg/g and 578.05 mg/g for arsenate (As(Ⅴ)), which are much higher than current similar adsorbents. The adsorption behaviors of As(Ⅲ/Ⅴ) follow pseudo-second-order kinetic model and Freundlich isotherm model, suggesting that both As(Ⅲ) and As(Ⅴ) are mainly chemisorbed onto MgO-CS-MnO 2 . It could perform effectively in a broad range of pH values (3−11), moreover, competing oxyanions (CO 3 2- , NO - , and SO 4 2- ), organic matters (humic acid) and ion strength exert no significant influence towards As remediation. XPS results revealed As(Ⅲ) adsorbed onto composite completely transformed to As(Ⅴ), and removal mechanisms involved oxidation and metal-O-As(Ⅲ/Ⅴ) complexation. In addition, it can be easily regenerated and recycled maintaining an excellent adsorption and oxidative ability. Besides, Column experiment demonstrated this composite column could effectively treat 1300 and 1700 bed volume (BV) of synthetic As(Ⅲ/Ⅴ)-contaminated groundwater, respectively. Therefore, MgO-CS-MnO 2 have a great potential applicability towards high As groundwater improvement as permeable reactive media.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2016
·
IF 0
Shen Qi,Xiao Jian Mao,Bao Yan Chai,Long Zhang
Transparent aluminum oxynitride (AlON) ceramics have been prepared through a method based on direct reaction sintering of alumina and aluminum nitride powders using MgO and Y2O3 as co-additives. The sintering additives could cause the formation of liquid phase during sintering, which would greatly promote the densification and eliminate pores. The grain size of AlON is about 50-100μm. The influence of different component of Al2O3 and AlN as well as sintering temperature on microstructure and optical properties of AlON have been studied. High transparent AlON ceramics with the in-line transmittance of 80.3% at 2000 nm wavelength have been prepared when the concentration of sintering additives was 0.16wt% Y2O3 and 0.02wt% MgO.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2021
·Vol. 100
·期 3
·414-422
·
IF 2.326
Li Limin,Zhao Gaoyang,Lei Li,Li Chengshan
Herein, the chelated precursor solution (Mg/BzAc) was synthesized using magnesium acetate as raw material and benzoylacetone as chemical modifier. The prepared solution was coated on (00 l )-oriented LaAlO 3 (LAO) single crystal substrate to fabricate the MgO/BzAc gel films. First, ultraviolet absorption spectroscopy was employed to analyze the ultraviolet photosensitivity of the MgO/BzAc gel films and the characteristic absorption peak corresponding to π-π* transition in Mg/BzAc chelate rings was detected at the wavelength of 329 nm. It is found that the intensity of this peak decreased gradually with increase in UV irradiation time, which indicates that the MgO/BzAc gel films exhibit good ultraviolet photosensitive properties. Then, MgO crystalline films with biaxial texture were prepared by heat-treating MgO/BzAc gel films at 850 °C in air for 60 min. Finally, micro-patterned MgO films with biaxial textures were prepared on the LAO substrate using photosensitive sol-gel lithography in combination with the above heat-treatment process.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Yanpeng Huang,Qiong Wu,Jingfan Yan,Fumin Chu,Yuming Xu,Dongmin Li,Hongjia Zhang,Sen Yang
Biochar loaded with MgO is a promising adsorbent for the removal and recovery of phosphate from aqueous solutions. However, its phosphate adsorption capacity is unsatisfactory, especially at low phosphate concentrations. Loading nanoscale MgO onto biochar is an effective strategy. Here, ultrafine MgO nanoparticles and MgO nanosheets were loaded onto biochar from steam-exploded straw (UMB and SMB) via an impregnation-precipitation-pyrolysis method. The crystal sizes of ultrafine MgO nanoparticles and MgO nanosheets were about 6–8 nm and 10–16 nm, respectively. The phosphate adsorption capacity of UMB at C 0 = 100 mg P L −1 was 219.4 mg P g −1 , which was higher than that of SMB (164.9 mg P g −1 ). The results suggest that surface precipitation was the dominant adsorption mechanism and the hydration process and the smaller particle size of MgO may play a key role in the superior phosphate removal by UMB. Removal tests in real low-concentration phosphate water samples showed that 0.05 g L −1 UMB could reduce the phosphate concentration from 0.17 mg P L −1 to 0.01 mg P L −1 . In addition, phosphate could be desorbed from UMB in varying environments, and therefore has the potential to be used in fertilizer production or directly as a slow-release fertilizer.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2023
·Vol. 13
·期 8
·1261
·
IF 2.7
Zhen Pei,Haixiao Huang,Xingzhong Guo,Jinming Zhang,Mingxing Chen
MgO–Al2O3–SiO2(MAS) glass–ceramics with controllable crystalline phases were successfully prepared using the melting method followed by heat treatment. The effects of the main components of glass on the crystallisation kinetics, nucleation, crystallisation and properties of glass–ceramics were investigated in detail. As the Al2O3and MgO contents increase and SiO2content decreases, the crystallisation peak temperature and activation energy of MAS glass decrease, while the crystal growth tends to follow a homogeneous nucleation crystallisation. The MAS glass nucleation temperature and time increase with higher concentrations of Al2O3and MgO and with a lower SiO2concentration. Mg2(Al4Si5O18) indialite and MgAl2O4spinel precipitate simultaneously in the MAS glass after crystallisation; the relative proportion of crystalline phases is related to the composition and crystallisation temperature. A higher SiO2content allows the formation of a dominant indialite phase, while higher MgO and Al2O3contents promote the formation of a dominant spinel phase. The MAS glass ceramic with a greater indialite phase has good dielectric properties with a dielectric constant of 6.499 and dielectric loss of 0.0064, while that of a higher spinel phase possesses improved mechanical properties, with a Vickers hardness of 715 Hv and a bending strength of 244.9 MPa.
研究领域:
材料科学
·
无机化学
✓ 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）