The bandwidth requirements of telecommunication network users increased rapidly during the last decades. Optical access technologies must provide the bandwidth demand for each user. The passive optical access networks (PONs) support a maximum data rate of 100 Gbps by using the Orthogonal Frequency Division Multiplexing (OFDM) technique in the optical access network. In this paper, the optical broadband access networks with many techniques from Time Division Multiplexing Passive Optical Networks (TDM PON) to Orthogonal Frequency Division Multiplex Passive Optical Networks (OFDM PON) are presented. The architectures, advantages, disadvantages, and main parameters of these optical access networks are discussed and reported which have many advantages to becoming next-generation broadband access networks.
Sustainable development (SD) is an improvement that meets present needs but jeopardizes the ability of new populations to do the same. It is vital to acquaint EFL students with the terminology and idiomatic expressions of this discipline. Nowadays, sustainable development and the environment have been prioritized in every aspect of life. Since culture and the teaching of Foreign language English cannot be separated, the English language becomes the mean of communication in health, economics, education, and politics. Thus, integrating sustainable development goals within language learning and teaching is very important. This descriptive quantitative study aims to investigate the perception of EFL pre-service teachers of sustainable develo
... Show MoreThe present investigation developed the ester prodrugs of Non-steroidal anti inflammatory drugs (NSAIDs), Mefenamic acid and Flurbiprofen by conjugating with the natural antioxidant, 4-methyl umbelliferone that resulted the formation of Mefenamic acid-umbelliferone ester prodrug and Flurbiprofen-umbelliferone ester prodrug .The principal objective this study is the synthesis of the ester prodrugs of NSAIDs with the enhanced therapeutic activity and minimized side effects. Prodrugs were synthesized by coupling method using N,N’- dicyclohexylcarbodiimide/4-dimethylaminopyrimidine, subjected to physical, chemical characterization, spectral characterization (IR, 1H NMR, 13C NMR and Mass spectra),hydro
... Show More
(4)
(2)
The present investigation revealed cytological variations for six species (Eruca sativa, Sisymbirium irio, Diplotaxis harra, Erucaria hispanica, Schimpera Arabica and Brassica tournefortii ) belong to the Brassicaceaefamily.The flower buds were collected from Al-Habania lake that located in Al-Anbar-Iraq. Using iron-acetocarmine squash technique in anther-smear studies which revealed a chromosomal anomalies such as Lagging/brddge chromosomes, Micronuclei & initiated delay of four daughter cells.The frequency of abnormalities ranged (0.04 - 0.77%) which indicated the unstable heredity source of most wildplants. The pollen grains viability was estimated using acetocarmine stain, viable grains had stained, while sterile grains had not.T
... Show MoreThe present investigation revealed cytological variations for six species (Eruca
sativa, Sisymbirium irio, Diplotaxis harra, Erucaria hispanica, Schimpera Arabica
and Brassica tournefortii ) belong to the Brassicaceaefamily.The flower buds were
collected from Al-Habania lake that located in Al-Anbar-Iraq. Using ironacetocarmine
squash technique in anther-smear studies which revealed a
chromosomal anomalies such as Lagging/brddge chromosomes, Micronuclei &
initiated delay of four daughter cells.The frequency of abnormalities ranged (0.04 -
0.77%) which indicated the unstable heredity source of most wildplants. The pollen
grains viability was estimated using acetocarmine stain, viable grains had stained,while st
Many of accurate inertial guided missilc systems need to use more complex mathematical calculations and require a high speed processing to ensure the real-time opreation. This will give rise to the need of developing an effcint
In this research, the structural and optical properties were studied for Bi2O3 and Bi2O3: Al thin films with different doping ratios ( 1, 2, 3 ) % , which were prepared by thermal evaporation technique under vacuum , with thickness ( 450 ± 20 ) nm deposited on glass substrates at room temperature ( 300 ) K , Structural measurements by ( XRD) techniques demonstrated that all samples prepared have polycrystalline structure with tetragonal structure and a preferred orientation [ 201 ] the &n
... Show MoreTi6Al4V thin film was prepared on glass substrate by RF
sputtering method. The effect of RF power on the optical properties
of the thin films has been investigated using UV-visible
Spectrophotometer. It's found that the absorbance and the extinction
coefficient (k) for deposited thin films increase with increasing
applied power, while another parameters such as dielectric constant
and refractive index decrease with increasing RF power.
Thin films of Mn2O3 doped with Cu have been fabricated using the simplest and cheapest chemical spray pyrolysis technique onto a glass substrate heated up to 250 oC. Transmittance and absorptance spectra were studied in the wavelength range (300 -1100) nm. The average transmittance at low energy was about 60% and decrease with Cu doping, Optical constants like refractive index, extinction coefficient and dielectric constants (εr), (εi) are calculated and correlated with doping process.
(2)
(1)
