Interplay of Strain, Growth Kinetics and Surface Bonding in Growth Modes and Dislocation Generation in Strained Heteroepitaxy

1990 ◽  
Vol 202 ◽  
Author(s):  
C. Snyder ◽  
J. Pamulapati ◽  
B. Orr ◽  
P. K. Bhattacharya ◽  
J. Singh
Keyword(s):  
Growth Kinetics ◽  
Strain Energy ◽  
Critical Thickness ◽  
Dislocation Generation ◽  
3 Dimensional ◽  
Growth Modes ◽  
Atomistic Modelling ◽  
Pseudomorphic Growth

ABSTRACTIn this paper we examine the role of strain and growth kinetics on the growth modes in pseudomorphic growth. Regimes below critical thickness and above critical thickness are examined. Based on atomistic modelling and in-situ RHEED and STM studies we show that a competition between surface chemical energy and strain energy is shown to lead to 3-dimensional blend mode for high strain pseudomorphy. Consequences for dislocation generation are discussed.

scholarly journals Strain driven phase transition and mechanism for Fe/Ir(111) films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chen-Yuan Hsieh ◽  
Pei-Cheng Jiang ◽  
Wei-Hsiang Chen ◽  
Jyh-Shen Tsay
Keyword(s):  
Phase Transition ◽  
Strain Energy ◽  
Critical Thickness ◽  
Face Centered Cubic ◽  
Strain Accumulation ◽  
Strained Layers ◽  
Heterogeneous Interfaces ◽  
Face Centered ◽  
Pseudomorphic Growth ◽  
Limited Distortion

AbstractBy way of introducing heterogeneous interfaces, the stabilization of crystallographic phases is critical to a viable strategy for developing materials with novel characteristics, such as occurrence of new structure phase, anomalous enhancement in magnetic moment, enhancement of efficiency as nanoportals. Because of the different lattice structures at the interface, heterogeneous interfaces serve as a platform for controlling pseudomorphic growth, nanostructure evolution and formation of strained clusters. However, our knowledge related to the strain accumulation phenomenon in ultrathin Fe layers on face-centered cubic (fcc) substrates remains limited. For Fe deposited on Ir(111), here we found the existence of strain accumulation at the interface and demonstrate a strain driven phase transition in which fcc-Fe is transformed to a bcc phase. By substituting the bulk modulus and the shear modulus and the experimental results of lattice parameters in cubic geometry, we obtain the strain energy density for different Fe thicknesses. A limited distortion mechanism is proposed for correlating the increasing interfacial strain energy, the surface energy, and a critical thickness. The calculation shows that the strained layers undergo a phase transition to the bulk structure above the critical thickness. The results are well consistent with experimental measurements. The strain driven phase transition and mechanism presented herein provide a fundamental understanding of strain accumulation at the bcc/fcc interface.

scholarly journals Revealing thermally-activated nucleation pathways of diffusionless solid-to-solid transition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minhuan Li ◽  
Zhengyuan Yue ◽  
Yanshuang Chen ◽  
Hua Tong ◽  
Hajime Tanaka ◽  
...  
Keyword(s):  
Strain Energy ◽  
Interface Energy ◽  
Colloidal System ◽  
Dislocation Generation ◽  
Thermally Activated ◽  
Transition Pathways ◽  
Particle Level ◽  
Athermal Nucleation ◽  
Dependent Pathway

AbstractSolid-to-solid transitions usually occur via athermal nucleation pathways on pre-existing defects due to immense strain energy. However, the extent to which athermal nucleation persists under low strain energy comparable to the interface energy, and whether thermally-activated nucleation is still possible are mostly unknown. To address these questions, the microscopic observation of the transformation dynamics is a prerequisite. Using a charged colloidal system that allows the triggering of an fcc-to-bcc transition while enabling in-situ single-particle-level observation, we experimentally find both athermal and thermally-activated pathways controlled by the softness of the parent crystal. In particular, we reveal three new transition pathways: ingrain homogeneous nucleation driven by spontaneous dislocation generation, heterogeneous nucleation assisted by premelting grain boundaries, and wall-assisted growth. Our findings reveal the physical principles behind the system-dependent pathway selection and shed light on the control of solid-to-solid transitions through the parent phase’s softness and defect landscape.

Growth kinetics study revealing the role of the MPA capping ligand on adjusting the growth modes and PL properties of CdTe QDs

CrystEngComm ◽  
2014 ◽  
Vol 16 (8) ◽  
pp. 1547-1552 ◽  
Author(s):  
Yang Huang ◽  
Zanyong Zhuang ◽  
Xiaogang Xue ◽  
Jinsheng Zheng ◽  
Zhang Lin
Keyword(s):  
Growth Kinetics ◽  
Kinetics Study ◽  
Cdte Qds ◽  
Growth Modes

38. Max Brodel (1870-1941): His artistic influence on surgical learning at John Hopkins Medical School

2007 ◽  
Vol 30 (4) ◽  
pp. 47
Author(s):  
P. Pace-Asciak ◽  
T. Gelfand
Keyword(s):  
New York ◽  
Neck Surgery ◽  
The United States ◽  
Spoken Word ◽  
Medical Illustration ◽  
3 Dimensional ◽  
Teaching Anatomy ◽  
Computer Based ◽  
Pathological Disease

Medical students depend on illustration to learn anatomical facts and details that may be too subtle for the written or spoken word. For surgical disciplines, learners rely on tools such as language, 2-dimensional illustrations, and 3-dimensional models to pass on important concepts. Although a photograph can convey factual information, illustration can highlight and educate the pertinent details for understanding surgical procedures, neurovascular structures, and the pathological disease processes. In order to understand the current role of medical illustration in education, one needs to look to the past to see how art has helped solve communication dilemmas when learning medicine. This paper focuses on Max Brodel (1870-1941), a German-trained artist who eventually immigrated to the United States to pursue his career as a medical illustrator. Shortly after his arrival in Baltimore, Brodel made significant contributions to medical illustration in Gynecology at John Hopkins University, and eventually in other fields of medicine such as Urology and Otolaryngology. Brodel is recognized as one of America’s most distinguished medical illustrators for creating innovative artistic techniques and founding the profession of medical illustration. Today, animated computer based art is synergistically used with medical illustration to educate students about anatomy. Some of the changes that have occurred with the advancement of computer technology will be highlighted and compared to a century ago, when illustrations were used for teaching anatomy due to the scarcity of cadavers. Schultheiss D, Udo J. Max Brodel (1870-1941) and Howard A.Kelly (1858-1943) – Urogynecology and the birth of modern medical illustration. European Journal of Obstetrics & gynecology and Reproductive Biology 1999; 86:113-115. Crosby C. Max Brodel: the man who put art into medicine. New York: Springer-Verlag, 1991. Papel ID. Max Brodel’s contributions to otolaryngology – Head and Neck surgery. The American Journal of Otology 1986; 7(6):460-469.

{10-12} Twinning Mechanism During In Situ Micro-Tensile Loading of Pure Mg: Role of Basal Slip and Twin-Twin Boundary Interaction

2020 ◽  
Author(s):  
Nicolò Maria della Ventura ◽  
Szilvia Kalácska ◽  
Daniele Casari ◽  
Thomas Edward James Edwards ◽  
Johann Michler ◽  
...  
Keyword(s):  
Twin Boundary ◽  
Basal Slip ◽  
Tensile Loading ◽  
Boundary Interaction

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

THE ROLE OF BACTERIAL COMMUNITIES ON IN-SITU ARSENIC AND IRON CYCLING IN RIVERBANKS ALONG THE MEGHNA RIVER, BANGLADESH

2020 ◽  
Author(s):  
Kimberly D. Myers ◽  
◽  
Katrina Lee Jewell ◽  
P.S.K. Knappett ◽  
Mehtaz M. Lipsi ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Iron Cycling

How Artefacts Do Leadership: A Ventriloquial Analysis

2021 ◽  
pp. 089331892199807
Author(s):  
Jonathan Clifton ◽  
Fernando Fachin ◽  
François Cooren
Keyword(s):  
Organizational Communication ◽  
Recent Work ◽  
Distributed Leadership ◽  
Network Theory ◽  
Actor Network Theory ◽  
Fine Grained ◽  
Naturally Occurring ◽  
Human Actors

To date there has been little work that uses fine-grained interactional analyses of the in situ doing of leadership to make visible the role of non-human as well as human actants in this process. Using transcripts of naturally-occurring interaction as data, this study seeks to show how leadership is co-achieved by artefacts as an in-situ accomplishment. To do this we situate this study within recent work on distributed leadership and argue that it is not only distributed across human actors, but also across networks that include both human and non-human actors. Taking a discursive approach to leadership, we draw on Actor Network Theory and adopt a ventriloquial approach to sociomateriality as inspired by the Montreal School of organizational communication. Findings indicate that artefacts “do” leadership when a hybrid presence is made relevant to the interaction and when this presence provides authoritative grounds for influencing others to achieve the group’s goals.

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