The paper reviews the past 11 years of literature on the application of diode lasers in Atomic absorption spectrometry with graphite furnaces (GF), plasmas and flames as atomizers. Experimental arrangements and techniques for powerful absorption measurements as well as the theoretical background are covered. The analytical possibilities of high-resolution spectroscopy, including Dopplerfree techniques for isotope selective measurements and isotope dilution analysis are discussed and various applications of element-selective detection by diode laser Atomic absorption in combination with separation techniques, such as liquid (LC) and gas chromatography (GC), and with laser ablation of solid samples, are presented.

The term electronegativity was introduced by Linus Pauling, who characterized on the basis of thermodynamic data from the energies of the single bonds. In present study, the Density Functional Theory (DFT) was used to calculate electronegativity of atoms. The base of calculation is similar to Pauling and Mulliken methods. The results indicate that the largest value of electronegativity for Fluorine atom and then plotted the electronegativity values versus to Atomic numbers. We have selected scale of electronegativity base on Pauling’s method. Also we presented an empirical formula for electronegativity calculation that the value of the electronegativity is a function of number of valence electron, in addition to ionization potential and electron affinity. Our novel strategy designed by Natural Population Analysis (NPA) method. All calculations were performed using B3LYP method and aug-cc-pVTZ, 6-311++G (2df), SDDALL and LANL2DZ basis set in Gaussian 03W.

In this paper, the concept of a family of local atoms in a 2-inner product space is introduced and then this concept is generalized to an Atomic system for an operator. Next a characterization of Atomic systems is proved. This characterization lead us to obtain a new frame which is a generalization of frames in 2-inner product spaces.

MP-AES is the ideal instrument for people looking to transition from Flame Atomic Absorption Spectroscopy (FAAS) to another technique. By using nitrogen as the source gas for the plasma, running costs are greatly reduced, and by removing the requirement for hazardous nitrous oxide and acetylene safety is greatly increased. Additionally the higher temperature nitrogen plasma atomization/ ionization source improves detection limits, linear range, and long term stability, and allow the sample preparation process to be greatly simplified.

The knowledge-based economy is considered as one of the important concepts that has been given special attention in the above-mentioned legal documents of the I. R. Iran, including the general policies of the Resistive economy. Knowledge-based economy is a basic need for developing countries such as Iran. Avoiding a knowledge-based economy greatly reduces competitiveness. Economics based on science and knowledge leads to the sustainable growth and development of society and ultimately the realization of a Resistive economy. Due to the importance of knowledge-based economy in the development of the country, the purpose of this study is to "study the current and favorable situation of Iran's economy based on knowledge-based economy-Resistive economy". The type of research is applied-developmental in terms of purpose. Also, in order to determine the current and favorable situation of Iran's economy based on knowledge-based economy-Resistive economy, a questionnaire was developed and analyzed using SPSS software and inferential statistics. The results showed that the situation of the variables "economic and institutional regime", " Information and communication technology" and " Resistive economy" in Iran in general does not have the desired average. However, the results show that the variables " educated and skilled population" and " innovation system " in Iran have a favorable average. To show the gap between the current and favorable situation of knowledge-based economy-Resistive economy variables in Iran, two-sample t-test was used, which according to the results, there is a significant difference between the current and favorable situation of all variables.

The purpose of this study was to design educational content of Green Chemistry Metrics for undergraduate chemistry students. Based on the purpose of the research, it was an applied-development type, and in terms of collecting and analyzing the data; a descriptive-analytical type is used. The statistical sample was a collection of books, articles, journals, and dissertations related to green chemistry which were selected and analyzed up to getting theoretical saturation. By reviewing related literature and investigating various sources on how to design the educational contents of the chemistry green, and also by directions of the field experts, during several revers phases of core coding, chapters were determined, then, according to the designated chapters, objectives were written for each topic in the target-content table. The results of this study showed that for the design of the content of training green chemistry measurements, two categories of mass measurements and environmental measurements can often be quantitatively evaluated in the twelve principles of green chemistry. In these two categories, there are various methods for assessing the greenness of a reaction (organic reaction synthesis) were identified, including Atomic economy, reaction mass efficiency, material recovery parameter, environmental factor, process mass intensity, and effective mass efficiency are presented in a conceptual framework.

The Atomic theory or the theory of individual substance is the result of the studies conducted by early Greek natural philosophers such as Leucippus and Democritus. This theory is based on the belief in fundamental particles and existence of void in the body. These atoms are infinite in number and form, enjoy permanent motion and corporeality, and are impenetrable. Their coming together and dispersion results in generation and corruption, and reordering them because of motion results in change and evolution. However, Aristotle and his followers rejected this theory because of their opposition to the views of early Greek philosophers. Some Islamic philosophers have agreed with this theory because of their interest in finding the cause of the emergence of being; however, they have created some changes in it; for example, they have rejected the eternity and finitude of these particles. Of course, some of them, such as Nizam, disagreed with the existence of undividable atoms. Nevertheless, the Atomic theory has become stronger with the advancements in natural sciences during the last three centuries and has led to numerous effects such as the great progress in Quantum physics and modern chemistry.

Ground state Positronium (Ps) formation and the 2s state of hydrogen atom by positron impact in the intermediate and high energy range have been studied within the framework of Eikonal direct approximation. The eikonal chargeexchange scattering amplitude and the differential and total cross sections have been computed by reducing the sixdimensional integrals to one-dimensional ones; the results have been compared with some existing theoretical results and the experimental findings.

Background & Aim: One of the induced major problem after bleaching treatments is enamel surface roughness increase, which can lead to increased risk of dental caries, plaque accumulation and later enamel discoloration. In this study the effect of adding CPP-ACP to home bleaching gel on enamel roughness was evaluated.Methods & Materials: in this experimental study, premolar teeth have been used. The samples divided in three groups (n=13) randomly. The roughness of each group was evaluated before the bleaching process with Atomic Force Microscopy. Samples was kept in Carbamide peroxide 20%, CP 20% and CPP-ACP (with 1: 1 ratio), CP 20% and CPP-ACP (with 1: 2 ratio) for 14 days, each day 4 hours. The roughness was evaluated two times after bleaching and the results were evaluated statistically. The gained data in each group were evaluated by PAIRED T-Test, and for intra-group analysis ANOVA and POST HOC test was used.Results: Surface enamel roughness before bleaching was same in all three groups. (p<0.4) The surface roughness after bleaching was increased in Carbamide peroxide 20% and decreased in group 1, significantly The increase was significant in first group (p=0.01), the decrease was not significant in second group, but significant in third group. (p=0.01) Conclusion: The 20% CP and CPP-ACP with 1: 2 ratio can significantly decrease the surface roughness in comparison to the primary roughness.