A single-crystalline semi-polar gallium nitride (11-22) was grown on m-plane (10-10) sapphire substrate by metal organic chemical vapor deposition. Three-step approach was introduced to investigate the grain size evolution for semi-polar (11-22) GaN. Such approach was achieved due to the optimized gallium to ammonia ratio and temperature variations, which led to high quality (11-22) oriented gallium nitride epilayers. The full width at half maximum values along (-1-123) and (1-100) planes for the overgrowth temperature of 1080°C were found to be as low as 0.37° and 0.49°, respectively. This was an indication of the enhanced coalescence and reduction in root mean square roughness as seen by atomic force microscopy. Surface analysis via atomic force microscopy indicated the orientation towards semi-polar plane. Field emission scanning electron microscopy analysis further indicates that higher temperature of 1080°C during the deposition of the overgrowth promoted closely packed surface coalescence. Room temperature Raman revealed that the overgrowth temperature of 1080°C portrayed compressive strain free as compared to other overgrowth temperature. Based on these results, the promising overgrowth temperature of 1080°C can be further utilized in future work for optoelectronics devices.
The scientific and technological developments and their practical applications in all fields of life in general and in the education field in specific have led to the emergence of variables in the educational structure, teaching methods and in education in their modern form which is consistent in its entirety with the spirit of the age. We today live the age of knowledge increase full of wide ranging scientific and technological developments. Thus life demands human capabilities of a special kind able to develop and innovate. Here the increasing significance emerges for taking care of the human powers through educational systems much different from those current traditional systems. System
... Show MoreThe main goal of this work is to obtain the plasma electron temperature Te by optical emission spectroscopy of low pressure microwave argon plasma, as a function of working pressure and microwave power. A plasma system was designed and constructed in our laboratory using a magnetron of domestic microwave oven with power 800W without any commercial part. The applied voltage on the magnetron electrical circuit is changed for the purpose of obtaining the variable values of the microwave power. The spectral detection is performed with a spectrometer of wavelength range (200−1000nm). The working pressure and magnetron applied voltage were 0.3-3.0mbar and 180-240V, respectively. Two methods had been applied to estimate the electron temperatu
... Show MorePreserving the independence and sovereignty of the countries of the South Caucasus region, establishing political and economic stability in the region, and supporting regional cooperation are the main elements of Turkish foreign policy towards the region. The South Caucasus region, which has historical and cultural ties between it and Turkey, is a bridge that links Turkey to Central Asia.
Turkey later developed advanced relations with Azerbaijan and Georgia. However, the same momentum was not achieved in terms of relations with Armenia because of the conflict over Nagorny Karabakh
... Show MoreThis paper describes the use of microcomputer as a laboratory instrument system. The system is focused on three weather variables measurement, are temperature, wind speed, and wind direction. This instrument is a type of data acquisition system; in this paper we deal with the design and implementation of data acquisition system based on personal computer (Pentium) using Industry Standard Architecture (ISA)bus. The design of this system involves mainly a hardware implementation, and the software programs that are used for testing, measuring and control. The system can be used to display the required information that can be transferred and processed from the external field to the system. A visual basic language with Microsoft foundation cl
... Show MoreThis research was designed to study effect of performance appraisal dimensions on organizational confidence.
Asset completion questionnaire was used to collect data of this research from a random simple represent forty employees who works in Iraqi Oil ministry. The main result of this research was positive relations and the effect between performance appraisal and organizational confidence. The research contains some conclusions, the main of it is unimplemented the performance appraisal results in the policies of employees in the ministry and it work in classic methods incentives and training.
The important recommendations must doing to achieve integrating between the result of pe
... Show MoreThe study aims to identify the students’ attitudes toward recent techniques’ use in teaching; using power point software and data show to facilitate teaching approaches as well as following the approach of lecture in giving subjects, do these techniques facilitate, increase, and tackle the difficulties of subjects, do these attitudes positive or negative?, and to what extent these techniques raise up students’ motivation.
The activation energy and optical band gap of different regions (p-type) polysilicon have been measured. Both microscopic studies and current-voltage characteristics of diodes prepared on different surface regions were carried out. Comparison of diodes parameters and microscopic studies indicate that the type of angles between boundaries has a significant effect on diodes parameters while the boundary lengths per unit area has less effect. The mechanism of Al-interaction with grain boundaries and their intersecting points at different temperature were also studies. The X-ray fluorescence spectrometry has been used for detection of diffused A1%.
Chemical spray pyrolysis technique was used at substrate temperature 250 ˚C with annealing temperature at 400 ˚C (for 1hour) to deposition tungsten oxide thin film with different doping concentration of Au nanoparticle (0, 10, 20, 30 and 40)% wt. on glass substrate with thickness about 100 nm. The structural, optical properties were investigated. The X-ray diffraction shows that the films at substrate temperature (250 ˚C) was amorphous while at annealing temperature have a polycrystalline structure with the preferred orientation of (200), all the samples have a hexagonal structure for WO3 and Au gold nanoparticles have a cubic structure. Atomic force microscopy (AFM) was used to characterize the morphology of the films. The optical pr
... Show MoreAim: This study aimed to compare different types of ligation methods to obtain maximum tooth movement with the least undesirable rotation. Methods: Titanium brackets bonded to acrylic canine teeth were ligated to straight stainless steel (SS) archwires using four ligation methods (figure-O and figure-8 elastics, SS ligatures, and Leone Slide ligatures). The teeth with the ligatures in place were stored in a water bath at 37ºC for 1 day, 1 week, 2, 4 or 6 weeks before testing. The teeth were retracted through softened wax along the archwire and the amount of tooth movement and degree of rotation were measured. Results: Slide ligatures showed the highest distance of tooth movement and degree of canine rotation followed by figure-O elastics
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