Hollow core photonic bandgap fibers provide a new geometry for the realization and enhancement of many nonlinear optical effects. Such fibers offer novel guidance and dispersion properties that provide an advantage over conventional fibers for various applications. Dispersion, which expresses the variation with wavelength of the guided-mode group velocity, is one of the most important properties of optical fibers. Photonic crystal fibers (PCFs) offer much larger flexibility than conventional fibers with respect to tailoring of the dispersion curve. This is partly due to the large refractive-index contrast available in the silica/air microstructures, and partly due to the possibility of making complex refractive-index structure over the fiber cross section. In this paper the fundamental physical mechanism has been discussed determining the dispersion properties of PCFs, and the dispersion in a gas filled hollow core photonic crystal fiber has been calculated. We calculate the dispersion of air filled hollow core photonic crystal fiber, also calculate the dispersion of N2 gas filled hollow core photonic crystal fiber and finally we calculate the dispersion of He gas filled hollow core photonic crystal fiber.
Background: Many types of instruments and techniques are used in the instrumentation of the root canal system. These instruments and techniques may extrude debris beyond the apical foramen and may cause post-instrumentation complications. The aim of this study was to evaluate the amount of apically extruded debris resulted by using 4 types of nickel-titanium instruments (WaveOne, TRUShape 3D conforming files, Hyflex CM, and One Shape files) during endodontic instrumentation. Materials and methods: Forty freshly extracted human mandibular second premolar with straight canals and a single apex were collected for this study. All teeth were cut to similar lengths. Pre-weighted glass vials were used as collecting containers. Samples were randoml
... Show MoreIt is no secret to anyone that studying and investigating books of jurisprudence, despite their suffering, is a pleasure that cannot be compared to pleasure, and it has benefits and importance that cannot be limited and summed up, and it has great fruits that researchers and students of knowledge reap, as well as enriching libraries with jurisprudential material, after dusting them and taking them out to the light of libraries to be seen. Researchers and scholars, generation after generation, so that this nation can benefit from this pioneering intellectual and scientific product that was written for us by our first ancestors of working scholars who enriched human civilization with this scientific material, which has become a beacon guid
... Show MoreIn recent years, the consideration of natural products as anti-inflammatory and antioxidative treatments has more interested worldwide. Moreover, natural products are easily obtained and are relatively safe the Royal jelly (RJ) is one of them. The current study was carried to evaluate the effects of pregabalin (PGB) on physiological activity of sperms, reproductive hormones assay and some biochemical analysis. Forty (40) male albino rats (10-weeks-old) were divided into four groups (10 rats each): G1 (treated with PGB drug, 150 mg/kg B.wt (Lyrica-Pfizer-Pharmaceutical Industries), G2 (treated with RJ 1g/kg), G3 (treated with PGB drug and RJ together), and G4 control treated with norma
The research aimed to prepare a measure of the importance of enlightenment, academic education, and applied skills for third-stage female students, including teaching methods from their point of view/College of Education and Sports Sciences/University of Baghdad/Al-Jadriyah. The researchers used descriptive description in the comprehensive research procedures, an appropriate methodology in achieving the research objectives, sufficient for interpretations, how important is the academic teacher’s knowledge of teaching methods for student learning, what are the roles that the learners have acquired from the academic teacher. The scale of importance and horror consists of 15 items. The research population includes female students of t
... Show MoreBackground: Orthodontic tooth movement is characterized by tissue reactions, which consist of an inflammatory response in periodontal ligament and followed by bone remodeling in the periodontium depending on the forces applied. These processes trigger the secretion of various proteins and enzymes into the saliva.The purpose of this study was to evaluate the activity of alkaline phosphatase (ALP) in saliva during orthodontic tooth movement using different magnitude of continuous orthodontic forces. Materials and Methods: Thirty orthodontic patients (12 males and 18 females) aged 17-23 years with class II division I malocclusion all requiring bilateral maxillary first premolar extractions were randomly divided into three groups according to t
... Show MoreThis piece of research work aims to study one of the most difficult reaction and determination due to continuous and rapid variation of reaction products and the reactants. As molybdenum (VI) aid in the decomposition of hydrogen peroxide in alkaline medium of ammomia, thus means a continuous liberation of oxygen which cuases and in a continuous manner a distraction in the measurement process. On this basis pyrogallol was used to absorbe all liberated oxygen and the result is an a clean undisturbed signals. Molybdenum (VI) was determined in the range of 4-100 ?g.ml-1 with percentage linearity of 99.8% or (4-300 ?g.ml-1 with 94.4%) while L.O.D. was 3.5 ?g.ml-1. Interferring ions (cations and anions) were studied and their main effect was red
... Show MoreThis research aims to find out the phonemic, dialect and semantic ailments that were interrogated by the book of the parsing of thirty surahs of the Noble Qur’an by Ibn Khalawiyeh, by examining some phonemic phenomena of Qur’anic expressions and their explanatory relationships that resulted in their occurrence, such as substitution and compression, as the sounds in a word are affected by one another, especially during performance and composition. This influence and influence is the tendency of the human being to the law of ease, facilitation, and the reduction of muscular effort in speech often, all for the purpose of obtaining phonemic harmony for the compound letters; To facilitate pronunciation; And get rid of the muscular effort
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