A numerical computation for determination transmission coefficient and resonant tunneling energies of multibarriers heterostructure has been investigated. Also, we have considered GaN/Al0.3Ga0.7N superlattice system to estimate the probability of resonance at specific energy values, which are less than the potential barrier height. The transmission coefficient is determined by using the transfer matrix method and accordingly the resonant energies are obtained from the T(E) relation. The effects of both well width and number of barriers (N) are observed and discussed. The numbers of resonant tunneling peaks are generally increasing and they become sharper with the increasing of N. The resonant tunneling levels are shifted inside the well by increasing the well width and vice versa. These features and the transmission coefficient as a function of incident energetic particles play an important role in fabrication of high speed devices and a good factor for determination the peak-to-valley ratio of resonant tunneling devices respectively.
Background: Polymers are very rarely used in their form. These modifications are carried out in order to improve the properties of polymers.Recently silver have been used successfully as antimicrobial (medical and dental) biomaterials that can prevent caries and infection of implants Purposes: The aim of the present in vitro study is to evaluate the effect of addition of silver nitrate to acrylic resin in different concentrationsthrough several tests part of these are: The effect of this additive on impact strength, transverse strength, and tensile strength of AgNO3 – loaded resin, and to assess any effect of addition of silver nitrate on coloration of acrylic resin. Materials and methods: Different concentrations of silver nitrate
... Show MoreAim: surface modification of titanium using fiber laser 1064 nm to enhance the bond strength to resin cement. Material and Methods: thirty titanium discs of 0.6 cm x 0.3 cm (diameter and thickness respectively) were categorized after preparation into three groups (n=10) as follows: control group with no surface treatment and two test groups were treated with fiber laser after estimation the appropriate parameters in the pilot study which are 81 ns pulse duration, 30,000 Hz frequency, 50 µm spot size and 10,000 mm/s scanning speed and different average power values (10 W and 20 W) depending on the tested group. Titanium discs surface characterization was performed by scanning electron microscope (SEM), a
... Show MoreThis study was conducted to evaluate the effects of black tea on Pseudomonas
aeruginosa isolated from eye infection. One hundred samples (corneal scrapings)
were obtained. Approximately, 77% of the cases were due to contact lens wear
followed by 15 % trauma and 8% with unknown history. The isolates identified as
P. aeruginosa were 30% (23/77 CL) and 25% (2/8 Unknown). On the other hand,
the Kirby-Bauer antibiotic sensitivity assay showed that 100% of the isolates were
sensitive to Neomycin, Gentamicin and Amikacin. While 91.6% were sensitive to
Carbenicillin and Ceftriaxone; 66.6% were sensitive to Cefotaxime and 0% were
sensitive to Tertacycline. Only two isolates were found to be multidrug resistant.
Screenin
Because of the rapid development and use of the Internet as a communication media emerged to need a high level of security during data transmission and one of these ways is "Steganography". This paper reviews the Least Signification Bit steganography used for embedding text file with related image in gray-scale image. As well as we discuss the bit plane which is divided into eight different images when combination them we get the actual image. The findings of the research was the stego-image is indistinguishable to the naked eye from the original cover image when the value of bit less than four Thus we get to the goal is to cover up the existence of a connection or hidden data. The Peak to Signal Noise Ratio(PSNR) and Mean Square Error (
... Show MoreThe present work aims to evaluate the content of some toxic metals in chemical and organic fertilizers purchased from local markets in Baghdad, Iraq. The analysis was performed by laser-induced breakdown spectroscopy (LIBS) system. The emission spectral lines of lead (Pb), chromium (Cr), cadmium (Cd) and cobalt (Co) have been recorded to determine the best peak representing each element according to the NIST database. The validity of the LIBS procedure was checked by cross-validating the obtained results using atomic absorption spectroscopy (AAS) with a maximum relative error of 5.3%. Moreover, for qualitative analysis, Pb I 296.64 nm emission line was determined to be superior for the evaluation of lead content in terms of three
... Show MoreIn this research paper, we explain the use of the convexity and the starlikness properties of a given function to generate special properties of differential subordination and superordination functions in the classes of analytic functions that have the form in the unit disk. We also show the significant of these properties to derive sandwich results when the Srivastava- Attiya operator is used.
Radio protective effects of metformin and its ability to alter the spontaneous and induced genotoxic and cytotoxic levels effects on human peripheral blood lymphocytes were investigated in this study. Metformin, a hypoglycemic oral drug, is a biguanide derived from Galega officinalis that is widely utilized in controlling type 2 diabetes mellitus. Whole blood samples from 10 healthy donors (5 males and 5 females) were exposed to two doses of gamma-rays (1 and 2 Gray). Lymphocytes in cultures were treated with metformin (10 and 50µM) before gamma-irradiation. Cytokinesis-block micronucleus test was used to evaluate the protective effects of metformin on radiation induced genomic damage, cytostasis and
... Show MoreThis research presents and discuss the results of experimental investigation carried out on geogrids model to study the behavior of geogrid in the loose sandy soil. The effect of location eccentricity, depth of first layer of reinforcement, vertical spacing, number and type of reinforcement layers have been investigated. The results indicated that the percentage of bearing improvement a bout (22 %) at number of reinforced layers N=1 and about (47.5%) at number of reinforced layers N=2 for different Eccentricity values when depth ratio and vertical spacing between layers are (0.5B and 0.75B) respectively
Treated effluent wastewater is considered an alternative water resource which can provide an important contribution for using it in different purposes, so, the wastewater quality is very important for knowing its suitability for different uses before discharging it into fresh water ecosystems. The wastewater quality index (WWQI) may be considered as a useful and effective tool to assess wastewater quality by indicating one value representing the overall characteristic of the wastewater. It could be used to indicate the suitability of wastewater for different uses in water quality management and decision making. The present study was conducted to evaluate the Al-Diwaniyah sewage treatment plant (STP) effluent quality based on wastewa
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