scholarly journals Photoconductivity on K-Feldspar

2021 ◽  
Author(s):  
Afam Uzorka
Keyword(s):  
Conduction Band ◽  
Thermal Excitation ◽  
Complex Relationship ◽  
A Current

In this paper the details of photoconductivity experiments on K crystal are presented. Photoconductivity measurements were inconclusive as to whether or not there was a current flowing during the 850 nm excitation of a feldspar sample. However there was a clear current when exciting the same sample with 515 nm light, but there was a complex relationship between the magnitude of the current and the number of emission photons counted. A model was developed to explain the photoconductivity results where electrons migrate through the conduction band aided by thermal excitation and tunneling.

scholarly journals A Daring Obedience: Ibn ʿArabī’s Futuwwa on the Right Side of the Law

2020 ◽  
Vol 4 (1-2) ◽  
pp. 38-65
Author(s):  
Cyrus Ali Zargar
Keyword(s):  
Social Construction ◽  
Social Influence ◽  
Intellectual History ◽  
Young Men ◽  
Complex Relationship ◽  
Divine Attributes ◽  
The Social ◽  
Theoretical Frame ◽  
The Right ◽  
A Current

Abstract While Sufi writings have largely depicted futuwwa as the selfless virtue of upright young men, there has been, throughout Islam’s intellectual history, an underlying current characterised by brave rebelliousness, a current tied to the virtue’s complex relationship with urban fraternal societies. This paper investigates Muḥyī al-Dīn Ibn ʿArabī’s (d. 638/1240) deliberate response to futuwwa’s implications of recalcitrance. Making a case for a law-abiding variety of the virtue, Ibn ʿArabī builds a theoretical frame in which this manly trait, one of consideration and altruism, mimics divine attributes, especially a divine calculating wisdom. In doing so, Ibn ʿArabī performs a role that Jeff Mitchell describes as the prerogative of noble elites, historically speaking, namely, the social construction of virtue. As is argued here, while Ibn ʿArabī makes a careful case for a law-abiding futuwwa, the lingering resonances of the virtue’s gangster associations indicate that social influence is, to a degree, reciprocal. That is, while Ibn ʿArabī’s framing of futuwwa makes a detailed and metaphysically-substantiated case for law-abidingness, his argument also suggests, however implicitly, that the virtue cannot completely escape its non-elite outlaw framework.

Electron Mobilities and Ranges in Liquid Ethers: Ion-like and Conduction Band Mobilities

1975 ◽  
Vol 53 (9) ◽  
pp. 1263-1274 ◽  
Author(s):  
Jean-Pol Dodelet ◽  
Gordon R. Freeman
Keyword(s):  
Activation Energy ◽  
Conduction Band ◽  
Low Temperatures ◽  
Optical Excitation ◽  
Relative Increase ◽  
Dielectric Constants ◽  
Thermal Excitation ◽  
Butyl Ether ◽  
Ion Migration ◽  
Free Ion

The free ion yields in X irradiated ethers are larger than those in alkanes because the dielectric constants of the former liquids are greater than those of the latter. The relative increase of the free ion yield with temperature is smaller in ethers than in alkanes because the dielectric constants decrease more rapidly with increasing temperature in the former. The density normalized penetration range (thermalization length) bGPd of the secondary electrons in dimethyl ether (DME) is 3.5 × 10−7 g/cm2. As the length of the n-alkyl groups on the ether is increased bGPd increases towards the value obtained for long chain n-alkanes, 4.5 × 10−7 g/cm2. Electron mobilities ue showed two types of behavior: (i) at low temperatures ue approaches a value of about 2u−, where u− is the mobility of the anions formed in the irradiated liquid; (ii) at higher temperatures the ratio ue/u− increases with temperature, and equals 21 in di-n-butyl ether (DBE) at 375 K. The activation energy of electron migration at low temperatures (ion-like mechanism) is similar to that of ion migration, 2–3 kcal/mol, while at high temperatures it increases to ∼6 kcal/mol. The larger activation energy is attributed to thermal excitation of electrons from the solvated state into a conduction band, and is equal to one-half of the optical excitation energy of the solvated electrons. Electrons in water, alcohols, and ammonia at 300 K migrate by the ion-like mechanism. Electrons in alkanes migrate almost exclusively by the conduction band mechanism. A plot of the Arrhenius temperature coefficient of electron mobility against mobility in different liquids at a given temperature displays a maximum which is temperature dependent.

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Novel magneto-optical recording materials: Bi-substituted garnet films

1991 ◽  
Vol 49 ◽  
pp. 776-777
Author(s):  
Takao Suzuki ◽  
Hossein Nuri
Keyword(s):  
Grain Size ◽  
Amorphous Film ◽  
Nitrogen Atmosphere ◽  
Optical Recording ◽  
Garnet Film ◽  
Media Noise ◽  
Garnet Films ◽  
Order Of Magnitude ◽  
A New Technique ◽  
A Current

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Rem Study of Current Effect on the Structure of Clean Si(111) Surface

1990 ◽  
Vol 48 (1) ◽  
pp. 306-307
Author(s):  
A. Yamanaka ◽  
H. Ohse ◽  
K. Yagi
Keyword(s):  
The Other ◽  
Current Direction ◽  
Clean Surface ◽  
Current Effect ◽  
Atomic Steps ◽  
Step Bunching ◽  
Terrace Width ◽  
Step Down ◽  
A Current

Recently current effects on clean and metal adsorbate surfaces have attracted much attention not only because of interesting phenomena but also because of practically importance in treatingclean and metal adsorbate surfaces [1-6]. In the former case, metals deposited migrate on the deposit depending on the current direction and a patch of the deposit expands on the clean surface [1]. The migration is closely related to the adsorbate structures and substrate structures including their anisotropy [2,7]. In the latter case, configurations of surface atomic steps depends on the current direction. In the case of Si(001) surface equally spaced array of monatom high steps along the [110] direction produces the 2x1 and 1x2 terraces. However, a relative terrace width of the two domain depends on the current direction; a step-up current widen terraces on which dimers are parallel to the current, while a step-down current widen the other terraces [3]. On (111) surface, a step-down current produces step bunching at temperatures between 1250-1350°C, while a step-up current produces step bunching at temperatures between 1050-1250°C [5].In the present paper, our REM observations on a current induced step bunching, started independently, are described.Our results are summarized as follows.(1) Above around 1000°C a step-up current induces step bunching. The phenomenon reverses around 1200 C; a step-down current induces step bunching. The observations agree with the previous reports [5].

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

Current Trends in the Training and Utilization of Paraprofessionals in Speech and Language Programs

1991 ◽  
Vol 22 (2) ◽  
pp. 51-59 ◽  
Author(s):  
Kathy L. Coufal ◽  
Allen L. Steckelberg ◽  
Stanley F. Vasa
Keyword(s):  
Selection Criteria ◽  
Job Descriptions ◽  
Paraprofessional Training ◽  
Language Programs ◽  
Program Administrators ◽  
Current Trends ◽  
Training And Supervision ◽  
Communicative Disorders ◽  
Supervision Practices ◽  
A Current

Administrators of programs for children with communicative disorders in 11 midwestern states were surveyed to assess trends in the training and utilization of paraprofessionals. Topics included: (a) current trends in employment, (b) paraprofessional training, (c) use of ASHA and state guidelines, and (d) district policies for supervision. Selection criteria, use of job descriptions, training programs, and supervision practices and policies were examined. Results indicate that paraprofessionals are used but that standards for training and supervision are not consistently applied across all programs. Program administrators report minimal training for supervising professionals.

Hearing Aids: A Current Overview

1978 ◽  
Vol 11 (3) ◽  
pp. 813-822
Author(s):  
Joel M. Mynders
Keyword(s):  
Hearing Aids ◽  
A Current
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