JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
Zhongshan Ren,Xiaojun Hu,Xiangxin Xue,Kuochih Chou
The solid state reactions in Fe 3 O 4 –TiO 2 system has been studied by diffusion couple experiments at 1323–1473 K, in which the oxygen partial pressure was controlled by the CO–CO 2 gas mixture. The XRD analysis was used to confirm the phases of the inter-compound, and the concentration profiles were determined by electron probe microanalysis (EPMA). Based on the concentration profile of Ti, the inter-diffusion coefficients in Fe 3 O 4 phase, which were both temperature and concentration of Ti ions dependent, were calculated by the modified Boltzmann–Matano method. According to the relation between the thickness of diffusion layer and temperature, the diffusion coefficient of the Fe 3 O 4 –TiO 2 system was obtained. According to the Arrhenius equation, the estimated diffusion activation energy was about 282.1 ± 18.8 kJ mol −1 .
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
RADIOCHIMICA ACTA
·
2021
·Vol. 110
·期 2
·107-119
·
IF 1.44
Yuzhen Sun,Hui Zhang,Rong Hua,Mingbiao Luo,Chuan-Pin Lee,Zhifen Wang,Weigang Liu,Jie Kong,Yunfeng Shi
Tamusu area is the primary pre-selection site of clayrock disposal repository for high-level radioactive waste (HLW) in China. However, the research on the migration behavior of nuclides in Tamusu clayrock is still in its infancy. For the first time in laboratory, the diffusion behavior of Re(VII) in Tamusu clayrock core was studied by means of through-diffusion method. The effects of pH, ionic strength and humic acid on the diffusion behavior of Re(VII) in clayrock were studied. The effective diffusion coefficient, apparent diffusion coefficient and rock capacity factor value were obtained. All the experimental conditions of Re(VII) diffusion in Tamusu clayrock are compared with other geological samples under the same conditions in literature data. The diffusion mechanism of radionuclide in Tamusu clay is discussed, which can provide experimental data for site selection and safety assessment of high-level radioactive waste repository in China. The experimental results showed an effective application and reference for the countries disposed HLW in mudrocks or clayrocks, such as France, Belgium etc. in Europe. Moreover, this research can provide the original data support for the metallogenic regularity and prospecting prognosis of rare element rhenium in different geological environments.
研究领域:
环境科学
·
核废料管理
·
地质学
·
放射化学
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2020
·Vol. 27
·期 9
·1216-1225
·
IF 1.713
Wei Wang,Yue Hong-rui,Xue Xiang-xin
This study investigated the interdiffusion of calcium ferrite/calcium titanate system in the time range of 0–120 min by the diffusion couple method in a CO/N 2 reducing atmosphere at 700°C. The results show that after the diffusion reaction occurred, no longitudinal agglomerations were present on the substrate surface on the calcium titanate side. When the diffusion time was increased to 105 min, a net vacancy flow from calcium titanate to calcium ferrite might have occurred, causing the surface of the calcium ferrite substrate to collapse. The thickness of the diffusion layer of the calcium ferrite/calcium titanate system was about 17–48 µm, which conforms to the parabolic law of diffusion. The diffusion coefficient and the Ti 4+ concentration in the calcium ferrite/calcium titanate system are related. This shows an increase in the diffusion coefficient with the increase of Ti 4+ concentration, and the diffusion coefficient value was in the range of 10 −12 –10 −11 cm 2 ·s −1 .
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
·
2015
·
IF 2.947
Chuande Huang,Xiaodong Wang,Xin Liu,Ming Tian,Tao Zhang
In this paper, the phase evolution, microstructure changes, and element diffusion for the formation of BaSnO 3 from BaCO 3 and SnO 2 were extensively investigated. It was found that BaCO 3 rapidly diffused on surface of SnO 2 at the initial stage of the reaction (approximately 700 °C), forming a uniform BaSnO 3 shell. Subsequently, BaSnO 3 grew via two different routes depending on the calcination temperature. When the reaction was carried out below 820 °C, BaSnO 3 phase further grew by diffusion of barium ions across BaSnO 3 layer to SnO 2 phase, since the BaSnO 3 interlayer prevented the direct reaction between surface BaCO 3 and SnO 2 core. Once a higher temperature above 820 °C was provided, Ba 2 SnO 4 were generated by reaction between BaCO 3 and BaSnO 3 shell. Under such circumstances, pure BaSnO 3 was obtained by diffusion of barium ions from Ba 2 SnO 4 across BaSnO 3 to SnO 2 . The rate-determining step in both cases was assigned to the diffusion of barium ions.
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
FUEL
·
2024
·
IF 6.7
Yuqi Su,Pengcheng Sun,Junshuai Chen,Maogang He,Ying Zhang
The transport properties including thermal diffusivity and Fick diffusion coefficient are of great significance to the optimization of heat and mass transfer processes in the combustion of gasoline. In this work, the thermal diffusivities and Fick diffusion coefficients of ethanol + isooctane binary mixtures were measured by dynamic light scattering method at mole fraction of ethanol x 1 = 0.1, 0.3, 0.5, 0.7 and 0.9, and over the temperature range from 323.15 K to 523.15 K along the isobaric lines including 2.5 MPa, 5 MPa, 7.5 MPa and 10 MPa. The variation of thermal diffusivity and Fick diffusion coefficient with the temperature, pressure and composition was analyzed to guide the optimization of combustion process. Four classic estimation models were used for the calculation of the thermal diffusivities of the binary mixtures of ethanol + isooctane. The Scheffé model has the best calculation performance with the average absolute relative deviations (AARD) of 2.09 %. The UNIDIF model was used to estimate the Fick diffusion coefficients of ethanol + isooctane with the AARD of 4.75 %.
研究领域:
化学工程
·
燃烧科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2020
·
IF 2.838
Junwei Cui,Shaomin Yan,Jiangtao Wu,Shengshan Bi
In this work, thermal and mutual diffusivity of n -heptane ( n -C 7 H 16 ) with dissolved carbon dioxide (CO 2 ) were simultaneously measured using dynamic light scattering (DLS) method from 298 to 473 K and saturation pressure up to 5.5 MPa. For this purpose, the DLS setup as well as temperature and pressure system were improved. Two hydrodynamic modes in connection with the statistical fluctuations of entropy and species were verified. The average expanded uncertainty of thermal and mutual diffusivity were 9.0% and 4.9% with a coverage factor of k = 2. The thermal and mutual diffusivity versus pressure under isothermal lines were briefly discussed and a comparison with literature was performed. The experimental thermal and mutual diffusivity measured in this work are in reasonable agreement with the literature data. This work is expected to provide fundamental data for engineering process .
研究领域:
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2021
·
IF 3.882
Yuehua Zhao,Yuyuan Lu,Dapeng Wang
Emulsions stabilized by both nanoparticles and surfactants often display longer shelf life than those stabilized by nanoparticles or surfactants alone. Although numerous works have been conducted to understand the effect of nanoparticles and surfactants on the variation of interfacial tension, little is known about interfacial diffusion when both nanoparticles and surfactants are present at interfaces. In this work, we used single-particle fluorescence tracking to study the lateral diffusion of individual hydrophobic nanoparticles at hexane–glycerol interfaces adsorbed by different amounts of nonionic surfactants. When the surfactant concentration is over a threshold, we found that the nanoparticle diffusion exhibits a two-regime behavior involving short-time Brownian and the emergence of subdiffusive, non-Gaussian, and dynamically anticorrelated diffusion in the long lag time regime. A stepwise analysis rationalized diffusion in different lag time regimes, leading to a mechanistic interpretation regarding the two-regime behavior. These results could provide insight into the understanding of the synergistic effect for the surfactant-assistant Pickering emulsion.
研究领域:
胶体科学
·
表面化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Hui Huang,Xiaowu Chen,Junmin Zhang,Jinshan Yang,Xiangyu Zhang,Yanmei Kan,Yudong Xue,Hao Qin,Xiao You,Shaoming Dong
As the promising candidates for hot section components used in gas turbines , SiC f /SiC composites suffer severe gas steam/melt corrosion, so their long-term stability depends on the surficial environmental barrier coatings . Here, we provide an alternative method to construct the protective structure by thermal diffusion . Firstly, Y-Al diffusants is diffused into the SiC substrate, forming a Y-Al diffusion layer . Then the diffusion layer can transform to a corrosion-resistant Y(Al)Si x O y layer after oxidative treatment. The compositions and morphologies of the as-received diffusion layer and the Y(Al)Si x O y layer were contrasted. Results show that a Y(Al)Si x O y protective layer, which thickens with the extension of oxidative treatment time and the increase of Y/Al ratio, can be formed on the SiC surface. Concentration gradient caused by preferential oxidation of Y-Al prompts the Y-Al diffusing towards surface. Meanwhile, the oxidation of Y-Al makes the Y(Al)Si x O y layer denser and thicker, and finally form the Y(Al)Si x O y protective layer.
研究领域:
材料科学
·
表面工程学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Simin Bi,Yumo Li,Jianpeng Ao,Zhijie Liu,Meilin Weng,Minbiao Ji
Numerous chemical reactions and most life processes occur in aqueous solutions, where the physical diffusion of small molecules plays a vital role, including solvent water molecules, solute biomolecules, and ions. Conventional methods of measuring diffusion coefficients are often limited by technical complexity, large sample consumption, or significant time cost. Here, we present an optical imaging method to study molecular diffusion by combining stimulated Raman scattering (SRS) microscopy with microfluidics: a “Y”-shaped microfluidic channel forming two laminar flows with a stable concentration gradient across the interface. SRS imaging of a specific molecule allows us to obtain a high-resolution chemical profile of the diffusion region at varying inspection locations and flow rates, which enables the extraction of diffusion coefficients using the convection–diffusion model. As a proof of concept, we measured diffusion coefficients of molecules including water, protein, and multiple ions, with a sample volume of less than 1 mL and a time cost of less than 10 min. Moreover, we demonstrated a high-resolution three-dimensional (3D) reconstruction of the diffusion patterns in the microfluidic channel. The high-speed microfluidic SRS platform holds the potential for quantitative measurements of molecular diffusion, chemical reaction, and fluidic dynamics at the liquid–liquid interfaces.
研究领域:
生物化学
·
光学成像
·
微流体技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 5
·1103-1113
·
IF 7.2
Wang Yan,Ni Peiyuan,Liu Yuling,Deng Tengfei
The enrichment of chromium in the magnetic iron chromite (Fe(Cr x Fe 1− x ) 2 O 4 ) phase is crucial for the recovery and recycling of chromium in stainless-steel pickling sludge. The kinetics and reaction mechanism of the solid-phase reaction between Fe 3 O 4 and Cr 2 O 3 were investigated using the diffusion couple method at 1473 K. Not only the diffusion behavior of Fe 2+ ions and Cr 3+ ions was elucidated, but also the solid solution behavior of Fe 3+ ions was discussed clearly. The microscopic morphology of the diffusion couple and the change in the concentrations of Fe and Cr cations across the diffusion layers were analyzed using scanning electron microscopy and energy dispersive spectroscopy. The self-diffusion coefficients of cations were calculated based on the concentration profiles of Fe and Cr, with the results indicating that the self-diffusion coefficient of the Fe ions was consistently higher than that of the Cr ions. Additionally, a mixture of Fe 3 O 4 and Cr 2 O 3 was annealed at 1373–1473 K for 1–5 h, and the kinetic parameters were calculated by studying the phase content of the product. The phase content of Fe(Cr x Fe 1− x ) 2 O 4 in the product was determined by Rietveld refinement of X-ray diffraction data, revealing that an activation energy ( E ) of 177.20 kJ·mol −1 and a pre-exponential factor ( B ) of 610.78 min −1 of the solid-phase reaction that produced the Fe(Cr x Fe 1− x ) 2 O 4 spinel.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2016
·Vol. 19
·期 1
·72-79
·
IF 3.849
Tao Yang,Jianmei Liu,Jinhui Dai,Yongsheng Han
Here, we report a general role of chemical diffusion and reaction in shaping particles. It is supposed that chemical diffusion and reaction play a role in shaping particles by changing the chemical distribution around the growth front of particles. Based on this understanding, three growth modes of particles are proposed in this paper, namely, reaction-limited mode, diffusion-limited mode, and reaction–diffusion balance mode. Silver particles are synthesized in different growth modes by various methods. No matter which method is employed, silver particles synthesized in the same mode have similar morphologies. To further generalize diffusion and reaction effects, copper and gold particles are synthesized. The morphological evolution of these two types of particles is similar to that of silver. These results indicate the general role of chemical diffusion and reaction in shaping particles, promising that a regulation on these two kinetic factors is a green and powerful technique for rational synthesis of materials.
研究领域:
材料科学
·
化学
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2016
·Vol. 311
·期 1
·655-661
·
IF 0.983
Wang Zhifen,Zhang Jianying,Chen Jiang,Zhang Zhiqiang,Zheng Qing,Li Jinying,Wu Tao
A through-diffusion method was used to investigate the Re(VII) (as a surrogate to 99 Tc(VII)) diffusion in compacted illite-, hematite- and limonite-montmorillonite mixtures. The effective diffusion coefficient D
e values were in the range of (4.29–6.71) × 10 −11 m 2 /s at pH 3.0 and (3.44–5.72) × 10 −11 m 2 /s at pH 9.0, respectively. Compared to montmorillonite, both D
e and α values enhanced at least three-folds in montmorillonite mixtures, indicating that the impurities changed the diffusion path. Interestingly, the K
d values of (0.63–3.94) × 10 −4 kg/m 3 were found in montmorillonite mixtures. However, the change of D
a value was less than two-folds, indicating that the illitization and iron corrosion of a back-fill material had no obvious influence on Re(VII) diffusion velocity.
研究领域:
环境科学
·
放射性废物管理
✓ 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）