Improved High Resolution Post-Transit Spectroscopy for Determining the Density of States in Amorphous Semiconductors

2000 ◽  
Vol 609 ◽  
Author(s):  
Charlie Main ◽  
Steve Reynolds ◽  
Rashad I. Badran ◽  
Joe M. Marshall
Keyword(s):  
Function Approximation ◽  
Delta Function ◽  
Amorphous Semiconductors ◽  
Rate Equations ◽  
Release Time ◽  
Disordered Materials ◽  
Trapping Rate ◽  
Laplace Inversion ◽  
Crystalline Materials ◽  
Release Times

ABSTRACTWe show that the analysis of post-transit photocurrent i(t) in a multi-trapping context to determine the density of trapping states g(E) is capable of resolving features less than kT in width. A commonly used method uses a Laplace inversion of i(t) data giving the well-known result g(E) ∼ t i(t) but employs a delta function approximation for trap release times, which results in loss of energy resolution. We show that it is possible to retain the exponential distribution function for trap release time and solve the multi-trapping rate equations directly, giving significantly improved resolution. The analysis is performed on computer generated post-transit data for distributed and discrete traps, and compared with the earlier method and other related Fourier transform methods for determining g(E). In addition, the versatility of the new method in handling cases with either distributed traps or with discrete traps means that it can be applied to disordered materials or to crystalline materials with well-defined defect levels.

Periodic Changes Effects of Distance between Magnetic Barriers on Electron Transport in Nanostructure

2011 ◽  
Vol 284-286 ◽  
pp. 833-838
Author(s):  
Zahra Bamshad
Keyword(s):  
Electron Transport ◽  
Spin Polarization ◽  
Function Approximation ◽  
Delta Function ◽  
Magnetic Configuration ◽  
Parallel Configuration ◽  
Magnetic Barriers ◽  
Spintronics Device ◽  
Periodic Changes

I theoretically investigate the spin Polarization and transmission of the electrons in a nanostructure consisting barriers with periodic, parallel and also anti parallel magnetization .also I investigate polarization when distance between barriers is constant, or is increased, or is decreased periodically. These observable quantities are found to be strongly affected by both the magnetic configuration and the number of the periodic magnetic barriers. When the number of periods increases, in parallel magnetization for periodic increasing distance the polarization is enhanced so in parallel configuration it is better that distance between barriers to be increasing periodically. I investigate Polarization in these configuration in both delta function approximation and modulated magnetic barriers in x direction. This Polarization can be used in spintronics device.

On the linear response of Bardeen–Cooper–Schrieffer superconductors I. clean superconductors

1986 ◽  
Vol 64 (10) ◽  
pp. 1396-1400
Author(s):  
Robert Cleary
Keyword(s):  
Function Approximation ◽  
Linear Response ◽  
Point Charge ◽  
Order Parameter ◽  
Pair Potential ◽  
Delta Function ◽  
Magnetic Vector Potential ◽  
Point Dipole ◽  
Magnetic Vector ◽  
Bare Potential

We calculate the linear response of a Bardeen–Cooper–Schrieffer superconductor to transverse and longitudinal electromagnetic radiation. Oscillations in the pair potential are also investigated. The order parameter and electric field of a point charge imbedded in a superconductor are also calculated. We assume a reasonable bare potential for the point charge. Finally, the linear response to the order parameter and magnetic vector potential is calculated for a reasonable model of a magnetic point dipole, again employing a more accurate model for the spin impurity than the usual delta-function approximation.

scholarly journals A Combinatorial 2-Approximation Algorithm for the Parallel-Machine Scheduling with Release Times and Submodular Penalties

Mathematics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 61
Author(s):  
Wencheng Wang ◽  
Xiaofei Liu
Keyword(s):  
Approximation Algorithm ◽  
Single Machine ◽  
Machine Scheduling ◽  
Parallel Machine Scheduling ◽  
Parallel Machine ◽  
Single Machine Scheduling ◽  
Release Time ◽  
Release Dates ◽  
Scheduling Problem ◽  
Release Times

In this paper, we consider parallel-machine scheduling with release times and submodular penalties (P|rj,reject|Cmax+π(R)), in which each job can be accepted and processed on one of m identical parallel machines or rejected, but a penalty must paid if a job is rejected. Each job has a release time and a processing time, and the job can not be processed before its release time. The objective of P|rj,reject|Cmax+π(R) is to minimize the makespan of the accepted jobs plus the penalty of the rejected jobs, where the penalty is determined by a submodular function. This problem generalizes a multiprocessor scheduling problem with rejection, the parallel-machine scheduling with submodular penalties, and the single machine scheduling problem with release dates and submodular rejection penalties. In this paper, inspired by the primal-dual method, we present a combinatorial 2-approximation algorithm to P|rj,reject|Cmax+π(R). This ratio coincides with the best known ratio for the parallel-machine scheduling with submodular penalties and the single machine scheduling problem with release dates and submodular rejection penalties.

scholarly journals Scheduling Two Identical Parallel Machines Subjected to Release Times, Delivery Times and Unavailability Constraints

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1025
Author(s):  
Adel M. Al-Shayea ◽  
Mustafa Saleh ◽  
Moath Alatefi ◽  
Mageed Ghaleb
Keyword(s):  
Parallel Machines ◽  
Release Time ◽  
Processing Unit ◽  
Scheduling Problem ◽  
Identical Parallel Machines ◽  
Central Processing ◽  
Cpu Time ◽  
Release Times ◽  
Delivery Times ◽  
Input Variables

This paper proposes a genetic algorithm (GA) for scheduling two identical parallel machines subjected to release times and delivery times, where the machines are periodically unavailable. To make the problem more practical, we assumed that the machines are undergoing periodic maintenance rather than making them always available. The objective is to minimize the makespan (Cmax). A lower bound (LB) of the makespan for the considered problem was proposed. The GA performance was evaluated in terms of the relative percentage deviation (RPD) (the relative distance to the LB) and central processing unit (CPU) time. Response surface methodology (RSM) was used to optimize the GA parameters, namely, population size, crossover probability, mutation probability, mutation ratio, and pressure selection, which simultaneously minimize the RPD and CPU time. The optimized settings of the GA parameters were used to further analyze the scheduling problem. Factorial design of the scheduling problem input variables, namely, processing times, release times, delivery times, availability and unavailability periods, and number of jobs, was used to evaluate their effects on the RPD and CPU time. The results showed that increasing the release time intervals, decreasing the availability periods, and increasing the number of jobs increase the RPD and CPU time and make the problem very difficult to reach the LB.

Elemental analysis of telatively thick specimens by EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1248-1249
Author(s):  
R.F. Egerton ◽  
S.C. Cheng
Keyword(s):  
Function Approximation ◽  
Core Loss ◽  
Delta Function ◽  
Mean Free Path ◽  
Specimen Thickness ◽  
Low Loss ◽  
Amorphous Silicon Dioxide ◽  
Edge Profile ◽  
Data Points ◽  
Inelastic Mean Free Path

Core-loss spectra of thicker specimens are strongly influenced by plural scattering. Plural inelastic events increase the background Ib underneath an ionization edge by an amount dependent on t/λ, t being the specimen thickness and λ the total-inelastic mean free path. However, plural scattering also contributes to the integral core-loss signal Ic. In fact, if the latter were integrated over a sufficiently large energy window Δ, the signal/background ratio (SBR=IC/Ib) might be expected to be independent of t.Figure 1 shows K-edge signal/background ratios for elemental carbon and silicon, presented as measured data points (for a collection semi-angle of l0mrad, 120keV incident energy and Δ=100eV) and as solid curves calculated by convolving a power-law edge profile with a delta-function approximation of the low-loss region. For silicon, SBR falls off more slowly with increasing t/λ, as expected from its higher edge energy. This trend is confirmed by measurements on amorphous silicon dioxide depicted in Fig.2, which shows the signal/background ratios of the oxygen and silicon K-edges as a function of thickness.

Discriminability of the Quality of Amplitude-Compressed Speech

1984 ◽  
Vol 27 (4) ◽  
pp. 571-577 ◽  
Author(s):  
Igor V. Náblek
Keyword(s):  
Compression Ratio ◽  
Critical Value ◽  
Normal Hearing ◽  
Hearing Impaired ◽  
Average Level ◽  
Release Time ◽  
Compressed Speech ◽  
Release Times ◽  
Masking Noise

In an earlier experiment on intelligibility of amplitude-compressed speech, subjects could not hear a difference between noncompressed speech and speech under some conditions of compression. Therefore, compression conditions were determined in which the quality of the two types of speech could be distinguished. When speech average level was 10 dB above a masking noise, compression ratio (CR) was equal to 2.5, and the attack time (Ta) was 3 ms, the release time (Tr) had to be shorter than 120 ms to achieve discrimination by trained normal-hearing subjects. With longer attack times and/or higher compression ratios, the critical value of release times increased. Thus, the range in which the discrimination was observed also increased (for CR = 5 and Ta = 10 ms, the critical Tr was 360 ms). The discrimination of our hearing-impaired subjects was much worse than that of the normal-hearing subjects. For example, speech processed with CR = 10, Ta = 1 ms, and Tr = 10 ms could be distinguished from the noncompressed by only 50% of the impaired subjects.

Effect of Hot Water Foot Bath on Gas Release and Pain After Cesarean

2021 ◽  
Vol 4 (2) ◽  
pp. 130-142
Author(s):  
Emine Aydın Turan ◽  
Yurdagül Yağmur
Keyword(s):  
Pain Scale ◽  
Hot Water ◽  
Release Time ◽  
Control Group ◽  
Gas Release ◽  
Control Groups ◽  
Release Times ◽  
Significant Difference ◽  
And Control ◽  
Experimental Group

Background: Post-cesarean pain is usually associated with wound and uterine contractions. Post-operative pain can impair organ function, delay mobilization and general recovery. It is known that the pain experienced in this period negatively affects the quality of life of the woman.Purpose: This study was carried out to determine the effect of hot water foot bath on pain and gas release after cesarean.Methods: This experimental type of research was conducted with women who had cesarean surgery between November 2018 and March 2020 in a private hospital. The population of the study included the women who had a cesarean delivery. A total of 70 women, including 35 experimental groups and 35 control groups, were sampled. Hot water foot bath was applied to the experimental group for 30 minutes, 3 hours after the operation. Data were collected with Introductory Information Form, Numerical Pain Scale, Experiment and Control Group Patient Follow-up Form after cesarean operation. Data were evaluated using number, percentage, arithmetic mean, standard deviation, repeated ANOVA, independent groups t test and chi-square test.Results: A statistically significant difference was found between the pain levels of women in the experimental and control groups (p <0.05) and pain levels of women in the experimental group were found to be lower. There was no statistically significant difference between the gas release times of women in the experimental and control groups (p> 0.05), but the gas release times of women in the experimental group were found to be shorter.Conclusion: It was found that the application of hot water foot bath in women who had cesarean surgery significantly reduced the level of pain but did not affect the gas release time

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