scholarly journals The Effects of Amorphous Layer Regrowth on Carbon Activation in GaAs and InP

1993 ◽  
Vol 316 ◽  
Author(s):  
A.J. Moll ◽  
J.W. Ager ◽  
K.M. Yu ◽  
W. Walukiewicz ◽  
E.E. Haller
Keyword(s):  
Hole Concentration ◽  
Amorphous Layer ◽  
Free Hole ◽  
Initial Results

ABSTRACTThe effect of the Ga dose on the activation of implanted carbon in GaAs is determined. The free hole concentration is found to depend on the depth of the amorphous layer created by the Ga co-implant. Initial results on C implantation in InP indicate the behavior of C is very different in InP when compared to GaAs. The role of precipitation in reducing the activation of C in both GaAs and InP is discussed.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

scholarly journals Microbial-Driven Stabilisation of Archaeological Iron Artefacts

2021 ◽  
Vol 2 (2) ◽  
pp. 274-292
Author(s):  
Sarah James ◽  
Edith Joseph
Keyword(s):  
Health And Safety ◽  
Chloride Content ◽  
Key Factors ◽  
Passivation Layers ◽  
Archaeological Iron ◽  
Initial Results ◽  
Sulphur Species ◽  
Partial Success ◽  
Made In

The instability of iron artefacts is rooted in salt contamination during burial and damages associated with exposure to alternative oxygen levels and high relative humidity once excavated. While a combination of chemical and mechanical treatments is utilised to remove the harmful ions (chlorides, sulphur species) and excess bulky corrosion products, these methods can be hazardous for conservation staff’s health, have limited success, or require extensive treatment times. Bio-based treatments provide a potentially greener alternative for removing damaging corrosion and creating biogenic mineral passivation layers, thus remediating concerns over costs, duration, and health and safety. Pseudomonas putida mt-2 (KT2440) is capable of utilising iron under certain conditions and for phosphating mild steel; however, applications have not been made in the cultural heritage sector. To address the potential of using bacteria for conservation purposes, Pseudomonas was assessed for both the bioremediation of salt contaminates and the production of a passivation layer suitable for iron artefacts, with specific conservation concerns in mind. Key factors for optimisation include the role of agitation, chloride content, and oxygen content on bacterial growth and biomineralisation. The initial results indicate a growth preference, not reliance, for NaCl and agitation with partial success of bioconversion of a mineral source.

An effective and efficient approach to p-type AlN by Be2:O codoping from first-principles calculations

2016 ◽  
Vol 30 (20) ◽  
pp. 1650257
Author(s):  
Meng Zhao ◽  
Wenjun Wang ◽  
Jun Wang ◽  
Junwei Yang ◽  
Weijie Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Ionization Energy ◽  
Hole Concentration ◽  
Valence Band Maximum ◽  
First Principles Calculations ◽  
Mutual Compensation ◽  
Efficient Approach ◽  
P Type ◽  
Codoping Method

Various Be:O-codoped AlN crystals have been investigated via first-principles calculations to evaluate the role of the different combinations in effectively and efficiently inducing p-type carriers. It is found that the O atom is favored to bond with two Be atoms. The formed Be2:O complexes decrease the acceptor ionization energy to 0.11 eV, which is 0.16 eV lower than that of an isolated Be in AlN, implying that the hole concentration could probably be increased by 2–3 orders of magnitude. The electronic structure of Be2:O-codoped AlN shows that the lower ionization energy can be attributed to the interaction between Be and O. The Be–O complexes, despite failing to induce p-type carriers for the mutual compensation of Be and O, introduce new occupied states on the valence-band maximum (VBM) and hence the energy needed for the transition of electrons to the acceptor level is reduced. Thus, the Be2:O codoping method is expected to be an effective and efficient approach to realizing p-type AlN.

The role of Golgi bodies in polysaccharide sulphation in Fucuszygotes

1978 ◽  
Vol 32 (1) ◽  
pp. 337-356
Author(s):  
M.E. Callow ◽  
S.J. Coughlan ◽  
L.V. Evans
Keyword(s):  
Cell Wall ◽  
Alginic Acid ◽  
Soluble Fraction ◽  
Amorphous Layer ◽  
Acceptor Molecule ◽  
Golgi Bodies ◽  
Isolation And Characterization ◽  
Fucus Serratus

The cell wall of 24-h zygotes of Fucus serratus is composed of 3 layers—an inner fibrillar layer (sulphated fucan), an outer fibrillar layer (alginic aicd/cellulose) and an exterior amorphous layer (sulphated fucan, alginic acid). The 2 layers containing sulphated fucan are preferentially thickened at the rhizoid pole. Light- and electron-microscope autoradiographic pulse-chase experiments on 22-h zygotes using 35SO2-(4) show the Golgi bodies to be the sites of fucan sulphation. The isolation and characterization of isolated Golgi-rich fractions from 22-h zygotes shows that the first detectable labelled macromolecule is associated with these fractions 2 min after addition of 35SO2-(4). The sulphate acceptor molecule has been partially characterized. 35S-APS and 35S-paps are detectable in the soluble fraction 0.5 min after addition of 35SO2-(4). The results are discussed in relation to other published work on the differentiation of Fucus embryos and on polysaccharide sulphation.

Social Media for Online Collaboration in Firms and Organizations

2016 ◽  
Vol 7 (1) ◽  
pp. 18-31 ◽  
Author(s):  
Enrico Franchi ◽  
Agostino Poggi ◽  
Michele Tomaiuolo
Keyword(s):  
Social Capital ◽  
Social Networking ◽  
Virtual Teams ◽  
Virtual Organizations ◽  
Social Aspects ◽  
Work Place ◽  
Online Networks ◽  
Networks Of Practice ◽  
Initial Results

Participation in social networks has long been studied as a social phenomenon according to different theories. In particular, the notion of social capital highlights a person's benefit due to his relations with other persons, including family, colleagues, friends and generic contacts. It may be important both for the individuals that are able to accumulate large amounts, and for organizations. Nowadays, social networking systems bring many acquaintances online, both in the private and working spheres. Some systems are used both at home, for leisure goals, and on the work place, professionally. In the vast majority of cases, social networking platforms are still used without corporate blessing. However, several traditional information systems, such as CRMs and ERPs, have also been modified in order to include social aspects. This article shows the role of social capital in the participation in online social networking activities, in the various cases of Virtual Organizations, Virtual Teams, and online Networks of Practice. It describes the present situation, which is characterized by great promises and mixed initial results, and some possible prospects.

Existence and role of an amorphous layer at the grain surfaces of YBa2Cu3O7 − δ ceramics obtained by solid state sintering

1990 ◽  
Vol 164-165 ◽  
pp. 1377-1384 ◽  
Author(s):  
J.M. Heintz ◽  
C. Magro ◽  
A. Tressaud ◽  
P. Dordor ◽  
J.P. Bonnet
Keyword(s):  
Solid State ◽  
Amorphous Layer ◽  
Solid State Sintering

Stability of Thermoelectromagnetic Convection

2006 ◽  
Author(s):  
Brent C. Houchens
Keyword(s):  
Numerical Solutions ◽  
Liquid Interface ◽  
Analytical And Numerical Solutions ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Initial Results

The role of thermoelectromagnetic convection (TEMC) on the stability of a range of flows is investigated. Here we discuss the general features of TEMC, and describe experiments in which this effect is thought to have significance. The general formulation for TEMC at a solid-liquid interface is presented. Initial results are benchmarked with existing analytical and numerical solutions.

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