Role of Nucleation and Growth in Two-Phase Microstructure Formation

Dense, polycrystalline MgO was infiltrated with monticellite (CaMgSiO4) liquid to study the penetration of liquid along the grain boundaries of MgO. Grain growth was found to be restricted with increasing amounts of liquid. The inter-granular regions were generally found to be comprised of a two-phase mixture: crystalline monticellite and a glassy phase rich in the impurities present in the starting MgO material. MgO grains act as seeding agents for the crystallization of monticellite. The location and composition of the glassy phase with respect to the MgO grains emphasizes the role of intergranular liquid during the devitrification process in “snowplowing” impurities present in the matrix.

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Preferred Orientations for Sol-Gel Derived Plzt Thin Layers

MRS Proceedings ◽

10.1557/proc-310-269 ◽

1993 ◽

Vol 310 ◽

Cited By ~ 107

Author(s):

Toshihiko Tani ◽

Zhengkui Xu ◽

David A. Payne

Keyword(s):

Heat Treatment ◽

Surface Energy ◽

Sol Gel ◽

Nucleation And Growth ◽

Thin Layers ◽

Energy Conditions ◽

Chemical Characteristics ◽

Interfacial Chemistry ◽

Si Substrates

AbstractPLZT thin layers were deposited onto various substrates by sol-gel methods, and crystallized under different conditions and substrate treatments. Relationships are given for the chemical characteristics of the substrate's surface and the preferred orientations which develop on heat treatment. A preferred (111) orientation always developed for perovskite crystallized on Pt layers which contained Ti on the surface. This was attributed to the formation of Pt3Ti and the role of heteroepitaxial nucleation and growth sites. In addition, a preferred (100) orientation was also obtained on unannealed Pt/Ti/SiO2/Si substrates which were free of Ti on the surface. This was attributed to self-textured growth with flat faces striving for minimum surface energy conditions. The results are discussed in terms of the importance of interfacial chemistry on the control of texture for crystallization of PLZT thin layers on coated substrates.

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Role of activation energies of individual phases in two-phase range on constitutive equation of Zr–2.5Nb–0.5Cu alloy

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(17)60020-7 ◽

2017 ◽

Vol 27 (1) ◽

pp. 172-183 ◽

Cited By ~ 8

Author(s):

K.K. SAXENA ◽

S.K. JHA ◽

V. PANCHOLI ◽

G.P. CHAUDHARI ◽

D. SRIVASTAVA ◽

...

Keyword(s):

Constitutive Equation ◽

Activation Energies ◽

Two Phase ◽

Phase Range

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Microstructure formation mechanism and corrosion behavior of FeCrCuTiV two-phase high entropy alloy prepared by different processes

Fusion Engineering and Design ◽

10.1016/j.fusengdes.2021.112792 ◽

2021 ◽

Vol 172 ◽

pp. 112792

Author(s):

Shaoqiu Xia ◽

Zhixin Xia ◽

Dong Zhao ◽

Yong Xie ◽

Xin Liu ◽

...

Keyword(s):

Corrosion Behavior ◽

Formation Mechanism ◽

High Entropy Alloy ◽

Microstructure Formation ◽

Two Phase ◽

High Entropy

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The role of graphene/graphene oxide in cement hydration

Nanotechnology Reviews ◽

10.1515/ntrev-2021-0055 ◽

2021 ◽

Vol 10 (1) ◽

pp. 768-778

Author(s):

Shaoqiang Meng ◽

Xiaowei Ouyang ◽

Jiyang Fu ◽

Yanfei Niu ◽

Yuwei Ma

Keyword(s):

Graphene Oxide ◽

Cement Paste ◽

Cement Hydration ◽

Isothermal Calorimetry ◽

High Mobility ◽

Nucleation And Growth ◽

Early Hydration ◽

Mobility Of Ions ◽

Cement Surface

Abstract Graphene (G) and graphene oxide (GO) have been shown to significantly improve the mechanical properties of cement-based materials. In this study, the effect of the G/GO on cement hydration was investigated. First, the zeta potential of G/GO in simulated solutions was tested, and the interaction between G/GO’s surface and Ca2+ was explored. Subsequently, scanning electron microscopy was used to observe the morphology of C–S–H nucleation and growth on the cement surface in the cement paste containing G/GO. Furthermore, XRD and TGA analyses were carried out on the hydration products of the sample. At last, isothermal calorimetry was applied to investigate the influence of G/GO on the early hydration of cement. The results showed that the addition of G/GO significantly accelerates C–S–H nucleation and growth on the cement surface. It is indicated that the high mobility ions derived by G/GO in the cement paste dominate the reason for the accelerated hydration of cement. The presence of G, especially GO, facilitates the mobility of ions, especially Ca2+, thus enhances the interaction between the cement surface and the ions. This strong interaction promotes the C–S–H nucleation and growth, and therefore, the hydration of the cement.

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Anomalies of continental precipitation associated with El Niño Southern Oscillation: the role of moisture contribution from oceanic and terrestrial sources

10.5194/egusphere-egu21-12386 ◽

2021 ◽

Author(s):

Rogert Sorí ◽

Raquel Nieto ◽

Margarida L.R. Liberato ◽

Luis Gimeno

Keyword(s):

South America ◽

Southern Oscillation ◽

The United States ◽

Precipitation Pattern ◽

Two Phase ◽

The North ◽

Terrestrial Origin ◽

Precipitation Anomalies ◽

June July

<p>The regional and global precipitation pattern is highly modulated by the influence of El Ni&#241;o Southern Oscillation (ENSO), which is considered the most important mode of climate variability on the planet. In this study was investigated the asymmetry of the continental precipitation anomalies during El Ni&#241;o and La Ni&#241;a. To do it, a Lagrangian approach already validated was used to determine the proportion of the total Lagrangian precipitation that is of oceanic and terrestrial origin. During both, El Ni&#241;o and La Ni&#241;a, the Lagrangian precipitation in regions such as the northeast of South America, the east and west coast of North America, Europe, the south of West Africa, Southeast Asia, and Oceania is generally determined by the oceanic component of the precipitation, while that from terrestrial origin provides a major percentage of the average Lagrangian precipitation towards the interior of the continents. The role of the moisture contribution to precipitation from terrestrial and oceanic origin was evaluated in regions with statistically significant precipitation anomalies during El Ni&#241;o and La Ni&#241;a. Two-phase asymmetric behavior of the precipitation was found in regions such the northeast of South America, South Africa, the north of Mexico, and southeast of the United States, etc. principally for December-January-February and June-July-August. For some of these regions was also calculated the anomalies of the precipitation from other datasets to confirm the changes. Besides, for these regions was calculated the anomaly of the Lagrangian precipitation, which agrees in all the cases with the precipitation change. For these regions, it was determined which component of the Lagrangian precipitation, whether oceanic or terrestrial, controlled the precipitation anomalies. A schematic figure represents the extent of the most important seasonal oceanic and terrestrial sources for each subregion during El Ni&#241;o and La Ni&#241;a.</p>

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Stretch goals and unethical behavior: role of ambivalent identification and competitive psychological climate

Management Decision ◽

10.1108/md-04-2019-0433 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Chang Chen ◽

Zhe Zhang ◽

Ming Jia

Keyword(s):

Unethical Behavior ◽

Psychological Climate ◽

Disruptive Effect ◽

Two Phase ◽

Content Type ◽

Mba Students ◽

Mediating Role ◽

Moderated Mediation Model ◽

Competitive Psychological Climate

PurposeThe purpose of this study is to examine the effect of stretch goals on unethical behavior and explore the mediating role of ambivalent identification and moderating role of competitive psychological climate.Design/methodology/approachA total of 350 MBA students from Northwestern China completed the two-phase survey. The bootstrapping analysis outlined by Hayes was used to assess a moderated mediation model.FindingsThis study found that stretch goals could trigger employees' unethical behavior via ambivalent identification. Competitive psychological climate intensified the relationship between stretch goals and ambivalent identification. Moreover, such a climate aggravated the indirect effect of stretch goals on unethical behavior via ambivalent identification.Practical implicationsOrganizations and managers should use stretch goals prudently and implement measures to reduce the ethical cost.Originality/valueThis study provides unique contributions by identifying ambivalent identification as an important mediator and competitive psychological climate as a boundary condition of stretch goals' disruptive effect on unethical behavior.

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