سید تقی محمدی

Summary: Gamma rays, like radio waves, infrared waves, ultraviolet rays, and X-rays, are a type of electromagnetic waves. The beginning of the use of radiation dates back to the end of the 19th century, after the discovery of X-rays by Rothengen. The use of radiation is widely and successfully seen in medicine, industry, agriculture and research sectors. For example, neutrons and gamma rays are used in medicine to treat cancerous tumors, and X-rays are used in radiology. In the defense and military industry, gamma rays emitted from radioactive radium and cobalt with high power. They are used to find small holes and fractures of metal parts in the aircraft and missile industry They are also used to determine the type and amount of radioactive material in aerial monitoring of gamma rays during identification operations. Another application of rays in the field of radiation processing. Ultra-processing is used in order to process and modify materials, reduce harmful industrial waste and reprocess waste water, etc., which is introduced in more detail in the rest of this article. Therefore, in this article, radiation and its types are first explained, and then the different types of gamma radiation systems are introduced, as well as some radiation emitters in the world are discussed.

In this paper, the optical properties of penta-boron carbide two-dimensional nanostructure (B2C) have been studied using simulations with computational codes based on density function theory based on initial calculations. The study of electronic properties shows that this two-dimensional nanostructure is an indirect semiconductor with an energy gap of 1.49 electron volts by the PBE approximation method. Study of optical properties of this nanostructure by PBE-GGA approximation method In addition to showing the agreement of optical aspects with the electronic properties of this two-dimensional monolayer, this nanostructure can in the future, as a suitable material in the design of electro-optical devices in industry Different to be used. According to the findings of this study based on the relatively high absorption rate and very low reflectivity of this nanomaterial in the visible spectrum, this nanostructure can be used for optical applications, especially in the design of solar energy devices and optical sensors with various applications in the defense industry.

In this paper, a new two-dimensional nanostructure called germanium sulfur diphosphide (GeP2S) structure, in the framework of the Density Functional Theory (DFT) has been predicted. In addition to studying the static and dynamic stability; structural properties of this two-dimensional nanostructure have also been compared with similar previous structures. The research findings indicate the acceptable stability of the proposed monolayer. The electronic aspects of this monolayer in the optimal state have been investigated and presented by two methods of hybrid function approximation (HSE06) and generalized gradient approximation method (GGA-PBE). The study of electron properties of this proposed monolayer introduces it as an indirect semiconductor with an energy gap of 1.367 eV by the HSE06 approximation and 0.688 eV by PBE-GGA approximation method. Study of optical properties of this proposed nanostructure indicate the agreement of optical band gap with the electronic band gap of this two-dimensional monolayer, especially in the HSE06 approximation method. Based on the findings of this study, due to the relatively high absorption rate and very low reflectivity in the visible spectrum in the energy range of 1 to 5 eV, if this proposed nanostructure is synthesized can be considered suitable for optical applications, especially in solar energy devices.

The purpose of this study was to determine the effectiveness of Mindfulness Education on Job Burnout and Educational Optimism in primary school teachers in Zanjan city. In this study, a semi-experimental design with pretest-posttest design with control group used and the statistical population of this research included elementary teachers in Zanjan city in 2017. The samples of study were selected using available sampling method. The sample consisted of 30 burnout teachers whose score in the Maslach Teacher's Burnout questionnaire was 1.5 out of the standard deviation higher than the mean. Individuals who were in the experimental group were included in a group for 8 weekly sessions in mindfulness education. The control group did not receive any intervention during this period. In order to record the changes, the Maslach Teacher Training Burnout Questionnaire (1986) and Beerd Teacher's Instructional Optimism Questionnaire (2010) completed before and after the intervention by the teachers. The statistical method of multivariate quarantine analysis was. The finding of this study showed that the effect of Mindfulness Education training had a significant effect on burnout and educational optimism, so that the burnout and educational optimism score increased significantly in the post-test phase(p<0/001). As a result Mindfulness training is effective on burnout and teachers' optimism.

Electronic and optical properties of pentagonal GeS2 monolayer are investigated by first principles calculations in the framework of the density functional theory. The stability of the nanostructure is confirmed by cohesive energy calculation, as well as phonon dispersion calculation. The electronic properties simulation indicates that GeS2 monolayer is an indirect band gap semiconductor with a band gap of about 0.9 eV. Furthermore, the optical properties investigation reveals that the material exhibits a very low absorption and reflectivity in visible region of the electromagnetic spectrum. However, it has a considerable absorption and reflectivity in the ultra violet region. The results of this study, therefore, suggest that the considered structure has a good potential application in the  new generation of opto-electronic devices, especially as a UV protection layer.

The present study aimed to investigate the effectiveness of self-compassion training program on psychological well-being and rumination of the mothers of children with special learning disabilities. Thirty Mothers of children with special learning disabilities were selected and divided into two groups. Psychological well-being questionnaire and rumination questionnaire were conducted as the pre-test. Then, the mothers of the experimental group attended in the self-compassion training program for eight sessions. The same survey was used as post-test on both groups. These values were compared through covariance analysis. The results showed a significant increase in psychological well-being and reduction in rumination of the mothers of the experimental group compared with the control group. Thus, the effectiveness of self-compassion training program on mental well-being and rumination of the mothers of children with special learning disabilities was confirmed.

Aging is a sensitive period of human life, in which aging people are at increased risk of chronic illness, social isolation and lack of social protection, and are often threatened in many cases, their autonomy by their physical and mental disabilities. The purpose of this study was to evaluate the effectiveness of self-compassion-focused therapy on loneliness and life expectancy in senior women. The present study was a semi-experimental design with a pretest-posttest design with the control group. The statistical population consisted of the elderly in Zanjan city, 30 of whom were eligible to participate in the research, they were randomly selected as samples and subjected to exprimental and control in two groups of 15 and completed the questionnaire of the loneliness of Russell and Miller's life expectancy. The experimental group received an 8-session self-compassion treatment, during which time the control group did not receive any psychological training or therapy. Data were analyzed by SPSS 21 software using covariance analysis. The results of this study showed that self-compassion-focused therapy could have a significant effect on reducing loneliness and increasing the life expectancy of senior women (P = 0.001). According to the importance of the elderly population in each community, it is suggested that self-compassion-focused education or treatment be used to reduce loneliness and increase life expectancy in this group.

Success in school is one of the most important goals of students which require appropriate social skills and psychological hardiness, so using effective intervention strategies to promote hardiness and social competence in schools seems to be essential for researchers and psychologists. The purpose of this study was to investigate the effect of positive thinking training on increasing psychological hardiness and social competence in students.

The research method was quasi-experimental with pretest - posttest - control group. The sample of this study consisted of 40 first grade students who were selected by cluster sampling and were randomly divided into two groups (20 students in each group). The experimental group received eight 90-minute sessions of positive thinking but the control group did not receive this intervention. Data were collected using Ahvaz Psychological Hardiness (Kiamarsi, (1998) questionnaire and Social Competence scale (Felner, 1990). Analysis of variance with repeated measures was used for data analysis

The results showed that the positive thinking training was effective on increasing psychological hardiness and social competence among the students, both in post-test and follow up stages (P<0/05).

Positive thinking helps people to evaluate stressful situations and problems with a positive attitude. Therefore, based on the results of the present study, positive thinking training has been able to develop psychological hardiness and social competence by generating positive mental thoughts and schemas in students.

The presence of a child with a disability or illness is very stressful for parents, and especially for mothers, because they experience tension, feelings of guilt, and fatigue. The purpose of this study was to investigate the effect of positive thinking skills training on social anxiety and cognitive avoidance of mothers of children with specific learning disabilities. The research method was semi-experimental and one-sample design with pre-test-post-test. The statistical population consisted of all mothers of children with special learning disabilities in Tarom city in 1396, among them 20 children were selected using convenient sampling method. The research instrument was social anxiety Inventory (Connor and et al, 2000) and cognitive avoidance questionnaire (Sexton and Dugas, 2004). Positive thinking was taught in 7 sessions of 120 minutes to experimental group. Data analysis was performed using Cohen's coefficient and Hedges coefficient. Data analysis using Cohen coefficient and g coefficient showed that the scores of the experimental group significantly decreased in the social anxiety and cognitive avoidance compared to the control group scores (p <0.01). Based on the results of this study, positive thinking skills have been effective to improve social anxiety and cognitive avoidance of mothers of children with special learning disabilities by creating mental and positive schema.