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排序方式: 共有1336条查询结果,搜索用时 15 毫秒
1.
In this study, MgO nanoparticles were successfully fabricated and incubated inside ZnO NPs to form MgO/ZnO nanocomposite for biomedical applications. The x-ray diffraction analysis of MgO, ZnO, and MgO/ZnO has shown the single-phase x-ray diffraction patterns through X'pert High score. The crystallite sizes were calculated as 18 nm, 42 nm, and 53 nm, respectively. The average particle size of MgO, ZnO, and MgO/ZnO nanopowders depicted from secondary electron images of field emission electron microscopy were 56 nm, 400 nm, and 450 nm, respectively. The presence of MgO NPs inside ZnO NPs was confirmed by transmission electron microscopy. The elemental dispersive spectroscopy of MgO, given the peaks of oxygen and magnesium, also showed only zinc and oxygen peaks in ZnO, which confirms no other impurities in MgO and ZnO powders. The elemental analysis of MgO/ZnO nanocomposite showed the peaks of Zinc and Oxygen, along with a tiny peak of Mg. The photoluminescence and UV–vis spectroscopy revealed the absorbance fluorescence limit of the nanomaterials. Fourier transform infrared spectroscopy confirmed the several groups present in the nanocomposite. The biocompatibility of MgO, ZnO, and MgO/ZnO was observed with human peripheral blood mononuclear cells. The cytotoxicity studies were also performed against human cancer (liver and breast) cell lines. The MgO, ZnO, and MgO/ZnO exhibited the antimicrobial properties against Escherichia coli and Staphylococcus aureus.  相似文献   
2.
为了提升MgO改性生物质炭的磷吸附能力,文章以花生壳为载体,利用碱式碳酸镁前驱体自组装-热解技术制备了结构有序的花瓣状MgO改性生物质炭吸附剂(FMgO-BC)。采用SEM,EDS,XRD,IR和TG表征了制备的FMgO-BC的物相结构与表面形貌,并研究了水解温度和Mg;浓度对FMgO-BC吸附性能的影响。研究结果表明,当水解温度为80℃,Mg2+浓度为0.6 mg/L时,FMgO-BC的吸附性能最优。文章还探究了FMgO-BC在不同pH值和加入量条件下的等温吸附模型和吸附动力学,研究结果表明,FMgO-BC的磷吸附动力学符合准二级动力学方程,等温吸附模型符合Langmuir等温吸附方程,理论最大吸附量为2221.89 mg/g,优于目前报道的MgO改性生物质炭的磷吸附性能。  相似文献   
3.
摘要:电炉冶炼钛铁矿制备酸溶渣时,为降低冶炼温度、保障渣的流动性,高钛渣中通常保留一定数量的氧化亚铁,导致后续钛白粉生产中产生硫酸亚铁,造成酸耗高等不利影响。针对上述问题,通过采用FactSage热力学分析结合电炉冶炼试验,研究了氧化镁对高钛渣物化性质影响规律及其降低炉渣冶炼温度的可行性。结果表明,提高氧化镁含量、降低氧化亚铁含量,高钛渣黏度变化不明显,但能降低炉渣熔化温度,并且提高氧化镁有利于抑制钛的还原。随着氧化镁含量提高,黑钛石固溶体中MgTi2O5比例增加。电炉冶炼结果表明,渣中氧化镁质量分数由6.6%提高到12.4%,可使冶炼温度降低50 ℃,所获得的炉渣主要物相为酸解性能良好的富镁黑钛石,对后续硫酸法钛白粉生产有利。  相似文献   
4.
5.
《Ceramics International》2022,48(8):10601-10612
Using MgC2O4, Mg powders as raw materials and Ni(NO3)2?6H2O as a catalyst, CNTs/MgO composite powders were prepared by a catalytic combustion synthesis method. The CNTs/MgO composite powders were characterized by XRD, Raman spectroscopy, FESEM/EDS and HRTEM. The effects of catalyst content on the degree of graphitization and aspect ratio of the CNTs in composite powders were investigated. Moreover, the thermal shock resistance of low-carbon Al2O3–C refractories after adding the composite powder was investigated. The results indicated that the CNTs prepared with 1 wt% Ni(NO3)2?6H2O addition had a higher degree of graphitization and aspect ratio. In particular, the aspect ratio could reach approximately 200. The growth mechanism of hollow bamboo-like CNTs in the composite powders was proven to be a V-L-S mechanism. The thermal shock resistance of Al2O3–C samples could be improved significantly after adding CNTs/MgO composite powders. In particular, compared with CM0, the residual strength ratio of Al2O3–C samples with added 2.5 wt% composite powders could be increased 63.9%.  相似文献   
6.
《Ceramics International》2021,47(24):34869-34880
This work complements an initial study regarding the mechanical behavior of MgO–C bricks at 1000 °C. In this case, two bricks bonded with phenolic resin, one of them containing aluminum, were treated at 600 °C and mechanically tested at RT and 600 °C. The thermal treatments attempt to simulate the in-service steelmaking ladle preheating process. At low temperatures, the binder pyrolysis is one of the main transformations and the Al melting neither its chemical reactions occur on a large scale yet. To evaluate the effects as the pyrolysis progresses, the soaking time at 600 °C was varied from 1 to 3 h. Although without significant chemical activity, the presence of Al affected the mechanical behavior of the tested bricks. The consolidation of the C–C network coming from the binder pyrolysis was identified as the main factor responsible for counterbalancing the material's degradation by microcracking. The heating combined with the low compressive pre-load applied on the tested specimens appears to close the microcracks and pores.  相似文献   
7.
Novel MgO-doped CaO sorbent pellets were prepared by gel-casting and wet impregnation. The effect of Na+ and MgO on the structure and CO2 adsorption performance of CaO sorbent pellets was elucidated. MgO-doped CaO sorbent pellets with the diameter range of 0.5-1.5 mm exhibited an excellent capacity for CO2 adsorption and adsorption rate due to the homogeneous dispersion of MgO in the sorbent pellets and its effects on the physical structure of sorbents. The results show that MgO can effectively inhibit the sintering of CaO and retain the adsorption capacity of sorbents during multiple adsorption-desorption cycles. The presence of mesopores and macropores resulted in appreciable change of volume from CaO (16.7 cm3∙mol1) to CaCO3 (36.9 cm3∙mol1) over repeated operation cycles. Ca2Mg1 sorbent pellets exhibited favorable CO2 capture capacity (9.49 mmol∙g1), average adsorption rate (0.32 mmol∙g1∙min1) and conversion rate of CaO (74.83%) after 30 cycles.  相似文献   
8.
In a sequence of temperature-dependent solid-state reactions in the system CaO–Al2O3MgO the formation of the ternary phase Ca3Al4MgO10 or C3A2M has been studied. Whereas the compound could not be prepared at 1200°C, a yield of 85 wt.-% of Ca3Al4MgO10 was obtained at 1320°C (incongruent melting point: 1330°C). Powder diffraction data compare well with results of previous investigations from the 1960s. Single crystals of Ca3Al4MgO10 could be retrieved from the sinter-pellets. Basic crystallographic data are as follows: orthorhombic symmetry, space group Pbcm, a = 5.14073(8), b = 16.7576(2), c = 10.70977(16) Å, V = 922.61(2) Å3, Z = 4. Using synchrotron diffraction data it was possible to solve the crystal structure. Least-squares refinements resulted in a residual of R(|F|) = 0.021 for 1000 independent observed reflections with I > 2σ(I) and 97 parameters. The structure contains [TO4]-tetrahedra (T=Al,Mg) forming a three-dimensional (3-D) framework whose topological characteristics have been determined. Al-Mg distributions on the different T-sites have been studied. The calcium cations are located in voids of the network. More than 50 years after its first observation our investigation clarifies the crystal structure of a compound belonging to a system that is of relevance for several fields of materials science.  相似文献   
9.
摘要:为了评估新型中间包微孔MgO耐火材料与钢液的反应性,系统测定了不同钢液与微孔MgO耐火材料表观接触角,研究了界面化学反应产物以及钢中夹杂物组成的变化。结果表明:含硫钢在微孔MgO耐火材料上铺展性最好,帘线钢次之,模具钢最差,主要是表面活性元素S降低了钢液表面张力所致;熔钢与耐火材料的界面行为中既包含了物理渗透又包含了化学反应。当界面处镁蒸气压极低时,一定的硅含量能导致MgO耐火材料被还原,界面处形成了大量镁橄榄石,从而降低了微孔MgO耐火材料的化学稳定性。钢液与耐火材料界面处的产物在很大程度上影响了钢中夹杂物组成,导致了夹杂物成分的改变。  相似文献   
10.
《Ceramics International》2022,48(11):15227-15235
High-performance and low-carbon MgO–C refractories are important refractories for smelting ultra-low carbon steel and clean steel. Based on this, Cr3C2/C composite powders were synthesized by the molten-salt method, and used as an additive to prepare low-carbon MgO–C refractories under nitrogen atmosphere. The phase, morphology and oxidation kinetics of Cr3C2/C composite powders were studied. In addition, the effect of Cr3C2/C composite powders on the morphology, mechanical properties, thermal shock resistance, and corrosion resistance of MgO–C refractories was investigated. The results indicated that the Cr3C2/C composite powders exhibited superior oxidation resistance than flake graphite. Moreover, the Cr3C2/C composite powders were introduced into the MgO–C refractories. Compared with the sample without Cr3C2/C composite powders, the introduction of 1 wt% Cr3C2/C composite powders significantly improved the thermomechanical properties and corrosion resistance of the material, its CMOR, CCS before and CCS after thermal shock were 9.06 MPa, 50.40 MPa and 32.60 MPa, respectively, and the corrosion index was significantly reduced from 44.6% to 26.5%.  相似文献   
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