Hydrogen Diffusion in the Hydrogen Collision Model of Amorphous Silicon Metastability

1999 ◽  
Vol 557 ◽  
Author(s):  
Howard M. Branz
Keyword(s):  
Diffusion Coefficient ◽  
Amorphous Silicon ◽  
Hydrogen Diffusion ◽  
Exchange Reactions ◽  
Collision Model ◽  
Long Time ◽  
Insight Into

AbstractThe trap-controlled model of H diffusion that underpins the H collision model of amorphous silicon metastability provides new insight into thermal and light-enhanced H diffusion in a-Si:H. The longstanding puzzle of the linear DB-dependence of diffusion coefficient with doping is resolved. Expressions for the light-induced H diffusion coefficient are derived with and without D-for-H exchange reactions. It is shown that D-for-H exchange does not affect the long-time diffusion coefficient that is measured under illumination.

Enhanced Hydrogen Diffusion Under Illumination in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
P.V. Santos ◽  
N.M. Johnson ◽  
R.A. Street
Keyword(s):  
Diffusion Coefficient ◽  
Electric Field ◽  
Experimental Evidence ◽  
Amorphous Silicon ◽  
Hydrogen Diffusion ◽  
Hydrogenated Amorphous Silicon ◽  
Diffusion Region ◽  
Hydrogen Diffusion Coefficient ◽  
Hydrogenated Amorphous ◽  
Carrier Population

ABSTRACTWe provide experimental evidence for the fact that hydrogen diffusion in hydroge-nated amorphous silicon is controlled by the concentration of electronic carriers. It is experimentally demonstrated that the hydrogen diffusion coefficient (a) is enhanced if the carrier population is increased by illumination and (b) is strongly suppressed if carriers are extracted from the diffusion region by the application of an electric field.

Concentration Dependence of Hydrogen Diffusion in Hydrogenated Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
W. Beyer ◽  
U. Zastrow
Keyword(s):  
Diffusion Coefficient ◽  
Amorphous Silicon ◽  
Concentration Dependence ◽  
Hydrogen Concentration ◽  
Hydrogen Diffusion ◽  
Band Model ◽  
Hydrogenated Silicon ◽  
Trapping Model ◽  
Hydrogen Implantation ◽  
Amorphous Si

ABSTRACTThe concentration dependence of hydrogen diffusion was studied in hydrogenated crystalline and amorphous silicon prepared by hydrogen implantation into crystalline Si wafers and into amorphous silicon of low hydrogen concentration. The results are compared with data for plasma-grown a-Si:H and µc-Si:H films. The increase of the diffusion coefficient with rising hydrogen concentration in a-Si:H is explained by an (equilibrium) energy band model of hydrogen diffusion whereas the decrease of the diffusion coefficient in c-Si:H is explained by a trapping model. The different behavior is attributed to a greater flexibility of the amorphous Si network compared to the crystalline Si lattice which is also visible in a difference in hydrogen-related microstructure formation.

Diffusion coefficient using pausing time of hydrogen in a-Si:H with exponential energy distribution

2015 ◽  
Vol 29 (14) ◽  
pp. 1550083 ◽  
Author(s):  
Harumi Hikita ◽  
Kazuo Morigaki
Keyword(s):  
Distribution Function ◽  
Diffusion Coefficient ◽  
Brownian Motion ◽  
Energy Distribution ◽  
Amorphous Silicon ◽  
Hydrogen Diffusion ◽  
Hydrogenated Amorphous Silicon ◽  
Diffusion Time ◽  
Energy Distribution Function ◽  
Hydrogenated Amorphous

The diffusion coefficient of hydrogen is obtained for exponential energy distribution in hydrogenated amorphous silicon (a-Si:H). It is shown that the diffusion coefficient follows the form of τα-1 (τ: diffusion time) in the case of α < 1 and a larger τ, in which α is the ratio of hydrogen temperature to width for energy distribution function. In the case of α ≥ 1, as α reaches infinity at the limit, the hydrogen diffusion approaches Brownian motion.

Anisotropy in the Dicke Narrowing of Rotational Raman Lines (A New Measure of the Nonsphericity of Intermolecular Forces)

1972 ◽  
Vol 50 (8) ◽  
pp. 778-782 ◽  
Author(s):  
B. K. Gupta ◽  
S. Hess ◽  
A. D. May
Keyword(s):  
Diffusion Coefficient ◽  
Physical Interpretation ◽  
Anisotropic Diffusion ◽  
Scattered Light ◽  
Intermolecular Forces ◽  
Gaseous Hydrogen ◽  
Experimental Results ◽  
Scattering Angle ◽  
Collision Model

The diffusion coefficient characterizing the Dicke narrowing of the rotational Raman lines, in general, depends on the polarizations of the incident and scattered light and on the scattering angle. Experimental results for the anisotropic diffusion coefficient are presented for 90° scattering and vv and vh polarizations of the S0(1) line in gaseous hydrogen. The physical interpretation of the observed anisotropy is given with the help of a simple collision model.

Bulinga izpausmes skolā: kriminoloģiskās problēmas

2021 ◽  
pp. 258-268
Author(s):  
Aldona Kipāne
Keyword(s):  
Theoretical Analysis ◽  
Research Methods ◽  
Complex Analysis ◽  
Health And Safety ◽  
Document Analysis ◽  
Violent Behaviour ◽  
Long Time ◽  
Empirical Research Methods ◽  
Insight Into

The article gives an insight into criminological problems of bullying in school phenomena. Although the term “bullying” is a modern word, such behaviour has been known for a long time. Bullying is a manifestation of violent behaviour, which threatens the victim's health and safety. The aim of this article is to describe and analyse bullying as a form of expression of violence, showing the criminological aspects of this phenomenon. To achieve the aim of the article the following tasks are defined: to provide the theoretical and practical framework of the research phenomenon, to study and evaluate certain elements of the criminological characterization of the bullying: the description of a victim and a perpetrator, the evaluation of factors and directions of prevention. Theoretical analysis methods such as deconstruction, descriptive and complex analysis, and empirical research methods – document analysis, comparison and compilation were employed in this study.

scholarly journals Hydrogen Diffusion Coefficient, Hydrogen Solution Coefficient and Hydrogen Permeability of Nb-TiNi Eutectic Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1131-1136
Author(s):  
Wei Liang Wang ◽  
Kazuhiro Ishikawa ◽  
Kiyoshi Aoki
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Absorption ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeability ◽  
K Value ◽  
Hydrogen Flow ◽  
Hydrogen Diffusion Coefficient ◽  
High K ◽  
Pressure Region ◽  
The Difference

In general, hydrogen permeabilityΦ of the alloy membrane is expressed as the product of the hydrogen diffusion coefficient D and the hydrogen solution coefficient K. Therefore, to improve the hydrogen permeability efficiently, the values of K and D should be separately considered. In the present study, hydrogen absorption and permeation behaviors of the Nb19Ti40Ni41 alloy consisting of the eutectic phase are investigated by measuring pressure-composition-isotherm (PCI) and by the hydrogen flow method and compared with those of palladium. The hydrogen absorption in the Nb19Ti40Ni41 alloy does not obey the Sieverts’ law in the pressure region of 0-1.0MPa at 523K, but it shows linear relationship between the difference in the square root of hydrogen pressure and hydrogen content between 0.1 and 0.4MPa. Although the value of D for the Nb19Ti40Ni41 alloy is considerably lower than that of palladium, its high K value enhances the hydrogen permeability Φ. It is suggested that the enhancement of D by microstructural control for Nb19Ti40Ni41 alloy is effective for improvement of Φ.

scholarly journals Role of Statues in the Artistic Commemoration of African Political Leaders: Analysis of 20 Selected National Statues in African Countries

2021 ◽  
Vol 3 (1) ◽  
pp. 40-77
Author(s):  
Kamau Wango
Keyword(s):  
Public Art ◽  
The Political ◽  
Human Beings ◽  
Political Leaders ◽  
African Countries ◽  
Long Time ◽  
The Subject ◽  
Visual Impact ◽  
Insight Into

Artistic commemoration of leaders and other iconic personalities has been in existence for centuries. Statues in particular have been used as a fitting avenue for the commemoration of political leaders and other luminaries in many fields. The premise upon which statues are made is that the subjects featured initiated and attained, in their lifetimes, concrete achievements that significantly impacted upon the lives of their fellow human beings. Other criteria for commemoration include proven integrity, dedication and selflessness in the service of the country and citizens. Statues as an integral part of public art have often generated substantial controversy on various fronts in many countries. Some of these gravitate around issues such as disputed likeness, queries about the fundamental achievements cited of the subject, at times open protests on the actions, character and integrity of the subject as well as the location of the statues. Other areas of contention include the implication of the presence of statues upon the political psyche of the country and their long-time impact on history, the youth and posterity. This paper examines the extent to which African countries have embraced this mode of artistic rendition to commemorate African political leaders in a way that is commensurate to their achievements. It is outside the scope of this paper to delve into the intricate web of back-and-forth arguments about the ‘concreteness’ of the legacies of the featured leaders who are mainly founding political figures of the respective countries. The paper, however, analyses the artistic essence of the selected statues in terms of their visual impact and whether they are indeed useful in articulating the legacies of the subjects and further, whether they ultimately bear ‘enduring visual value’ that spurs conversation and insight into these legacies. Statues must, at the very least, spur debate and conversation into the legacy of the featured subject. It becomes a form of constant interrogation as history itself takes its course; controversy is not necessarily a negative occurrence since it forms part of this discourse. The concept of immortalization, which is what initiators of statues often hope for is much harder to achieve and difficult to define. The paper examines 20 statues of African political leaders in different African Countries.

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