scholarly journals Understanding the electrochemistry of “water-in-salt” electrolytes: basal plane highly ordered pyrolytic graphite as a model system

2020 ◽  
Vol 11 (27) ◽  
pp. 6978-6989 ◽  
Author(s):  
Pawin Iamprasertkun ◽  
Andinet Ejigu ◽  
Robert A. W. Dryfe
Keyword(s):  
Basal Plane ◽  
Pyrolytic Graphite ◽  
Model System ◽  
Concentrated Solutions ◽  
Highly Ordered Pyrolytic Graphite ◽  
System P ◽  
The Stability ◽  
Stability Of Water

The stability of water-in-salt electrolyte systems is investigated using highly concentrated solutions of KF(aq) with graphite as a model system.

Electrochemically controlled winding and unwinding of substrate-supported carbon nanoscrolls

2018 ◽  
Vol 20 (8) ◽  
pp. 5900-5908 ◽  
Author(s):  
H. Tarábková ◽  
Z. Zelinger ◽  
P. Janda
Keyword(s):  
Electrolyte Solution ◽  
Basal Plane ◽  
Aqueous Electrolyte ◽  
Pyrolytic Graphite ◽  
Aqueous Electrolyte Solution ◽  
Highly Ordered Pyrolytic Graphite ◽  
Carbon Nanoscrolls

Carbon nanoscrolls (CNSs) formed spontaneously on the basal plane of highly ordered pyrolytic graphite (HOPG) show winding and unwinding movements when potential steps from 0 V to −0.5 V, −0.6 V and −0.9 V are applied on HOPG immersed in an aqueous electrolyte solution (0.1 M H2SO4).

High Rake Angle Orthogonal Machining of Highly Ordered Pyrolytic Graphite Parallel to the Basal Plane

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
B. Jayasena ◽  
S. Subbiah ◽  
C. D. Reddy
Keyword(s):  
Basal Plane ◽  
Pyrolytic Graphite ◽  
Rake Angle ◽  
Machining Process ◽  
Dynamic Simulations ◽  
Kink Bands ◽  
Orthogonal Machining ◽  
Highly Ordered Pyrolytic Graphite ◽  
Graphite Sheets

High rake angle orthogonal machining of highly ordered pyrolytic graphite (HOPG) parallel to the basal plane was carried out to synthesize few layers of graphene. The quality of the graphite sheets was found to be an alliance of any pre-existing defects in the HOPG and the nature of the machining process itself. Presence of pre-existing defects such as kinks and discontinuous layers were observed during the lateral examination of HOPG structure prior to machining. Evidence of flat, folded, and rolled structures were found in exfoliated graphite sheets in addition to defects such as two types of kink bands. Multiple spikes in measured cutting forces were seen during machining due to disturbances in tool movement. Molecular dynamic simulations were carried out to support the argument that specific pre-existing defects such as discontinuous layers cause the marked disturbances during machining.

Nanobubble-assisted formation of carbon nanostructures on basal plane highly ordered pyrolytic graphite exposed to aqueous media

2010 ◽  
Vol 21 (9) ◽  
pp. 095707 ◽  
Author(s):  
Pavel Janda ◽  
Otakar Frank ◽  
Zdeněk Bastl ◽  
Mariana Klementová ◽  
Hana Tarábková ◽  
...  
Keyword(s):  
Basal Plane ◽  
Carbon Nanostructures ◽  
Pyrolytic Graphite ◽  
Aqueous Media ◽  
Highly Ordered Pyrolytic Graphite

scholarly journals Capacitance of Basal Plane and Edge-Oriented Highly Ordered Pyrolytic Graphite: Specific Ion Effects

2019 ◽  
Vol 10 (3) ◽  
pp. 617-623 ◽  
Author(s):  
Pawin Iamprasertkun ◽  
Wisit Hirunpinyopas ◽  
Ashok Keerthi ◽  
Bin Wang ◽  
Boya Radha ◽  
...  
Keyword(s):  
Basal Plane ◽  
Pyrolytic Graphite ◽  
Highly Ordered Pyrolytic Graphite ◽  
Specific Ion Effects ◽  
Ion Effects

Effect of Storage on the Stability of Water Soluble Annatto Dye Formulation in a Simulated Orange-RTS Beverage Model System

LWT ◽  
2002 ◽  
Vol 35 (7) ◽  
pp. 617-621 ◽  
Author(s):  
P.G. Prabhakara Rao ◽  
A. Satyanarayana ◽  
D.G. Rao
Keyword(s):  
Model System ◽  
Water Soluble ◽  
The Stability ◽  
Stability Of Water

Shock-Induced Martensitlc Transformation of Highly Oriented Graphite to Diamond

1992 ◽  
Vol 270 ◽  
Author(s):  
David. J. Erskine ◽  
William. J. Nellis
Keyword(s):  
Crystal Structure ◽  
Shock Wave ◽  
Pyrolytic Graphite ◽  
Orientational Order ◽  
Stability Limit ◽  
Highly Ordered Pyrolytic Graphite ◽  
Graphite Structure ◽  
Wave Profiles ◽  
Onset Pressure ◽  
The Stability

ABSTRACTShock-wave profiles of highly ordered pyrolytic graphite shocked normal to the basal plane of the graphite crystal structure have been measured. For graphite with sufficient orientational order a martensitic transformation to a diamond-like phase is observed with a transition onset pressure 19.6±0.7 GPa, the stability limit of the graphite structure under shock compression. The minimum overpressure required for the transformation is not more than 6 GPa.

Comparison of TEM and STM observations of small silver clusters on different carbon supports

1990 ◽  
Vol 48 (4) ◽  
pp. 264-265
Author(s):  
Bernd Tesche ◽  
Tobias Schilling
Keyword(s):  
Vibration Isolation ◽  
Pyrolytic Graphite ◽  
Carbon Film ◽  
Silver Clusters ◽  
Carbon Supports ◽  
Stacking Order ◽  
System P ◽  
High Resolution Tem ◽  
High Degree ◽  
Degree Of Order

The objective of our work is to determine:a) whether both of the imaging methods (TEM, STM) yield comparable data andb) which method is better suited for a reliable structure analysis of microclusters smaller than 1.5 nm, where a deviation of the bulk structure is expected.The silver was evaporated in a bell-jar system (p 10−5 pa) and deposited onto a 6 nm thick amorphous carbon film and a freshly cleaved highly oriented pyrolytic graphite (HOPG).The average deposited Ag thickness is 0.1 nm, controlled by a quartz crystal microbalance at a deposition rate of 0.02 nm/sec. The high resolution TEM investigations (100 kV) were executed by a hollow-cone illumination (HCI). For the STM investigations a commercial STM was used. With special vibration isolation we achieved a resolution of 0.06 nm (inserted diffraction image in Fig. 1c). The carbon film shows the remarkable reduction in noise by using HCI (Fig. 1a). The HOPG substrate (Fig. 1b), cleaved in sheets thinner than 30 nm for the TEM investigations, shows the typical arrangement of a nearly perfect stacking order and varying degrees of rotational disorder (i.e. artificial single crystals). The STM image (Fig. 1c) demonstrates the high degree of order in HOPG with atomic resolution.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Stability and Folding of the Unusually Stable Hemoglobin from Synechocystis is Subtly Optimized and Dependent on the Key Heme Pocket Residues.

2020 ◽  
Vol 27 ◽  
Author(s):  
Sheetal Uppal ◽  
Mohd. Asim Khan ◽  
Suman Kundu
Keyword(s):  
Molten Globule ◽  
Life Forms ◽  
Model System ◽  
Heme Pocket ◽  
The Past ◽  
Specific Manner ◽  
Delivery Vehicles ◽  
The Stability ◽  
Key Residues ◽  
Synechocystis Sp

Aims: The aim of our study is to understand the biophysical traits that govern the stability and folding of Synechocystis hemoglobin, a unique cyanobacterial globin that displays unusual traits not observed in any of the other globins discovered so far. Background: For the past few decades, classical hemoglobins such as vertebrate hemoglobin and myoglobin have been extensively studied to unravel the stability and folding mechanisms of hemoglobins. However, the expanding wealth of hemoglobins identified in all life forms with novel properties, like heme coordination chemistry and globin fold, have added complexity and challenges to the understanding of hemoglobin stability, which has not been adequately addressed. Here, we explored the unique truncated and hexacoordinate hemoglobin from the freshwater cyanobacterium Synechocystis sp. PCC 6803 known as “Synechocystis hemoglobin (SynHb)”. The “three histidines” linkages to heme are novel to this cyanobacterial hemoglobin. Objective: Mutational studies were employed to decipher the residues within the heme pocket that dictate the stability and folding of SynHb. Methods: Site-directed mutants of SynHb were generated and analyzed using a repertoire of spectroscopic and calorimetric tools. Result: The results revealed that the heme was stably associated to the protein under all denaturing conditions with His117 playing the anchoring role. The studies also highlighted the possibility of existence of a “molten globule” like intermediate at acidic pH in this exceptionally thermostable globin. His117 and other key residues in the heme pocket play an indispensable role in imparting significant polypeptide stability. Conclusion: Synechocystis hemoglobin presents an important model system for investigations of protein folding and stability in general. The heme pocket residues influenced the folding and stability of SynHb in a very subtle and specific manner and may have been optimized to make this Hb the most stable known as of date. Other: The knowledge gained hereby about the influence of heme pocket amino acid side chains on stability and expression is currently being utilized to improve the stability of recombinant human Hbs for efficient use as oxygen delivery vehicles.

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