In this thesis, we intend the the electronic properties of boron - phosphide monolayer under applying perpendicular electric and magnetic fields. We study the beharier of electronic density of states of the thestruclure and temperature beharier of tra  ort preperties such as electrical and thermal conduetivities. We have found the results based on Green's function and many body approaches. Tight binding model in the presence of bias voltage and Zeeman effects due to external magnetic field has been applied to study electron dynamics. Using electronic band structure in the context of Green's function and linear respense theory, the mentioued physical preperties have been analysed. Moreover, the effects of electric and megnetic fields intensities and electron doping on the temperature behavior of conductivities and density of states of states have been investigated.

Abstract Transition metal sulfides (TMDs) possess exceptional dielectric properties and a narrow band gap, rendering them highly efficient as electromagnetic absorbing materials. Among these TMDs, the two-dimensional MoS2 nanosheet has received significant attention in research. However, the quest for new absorbers no longer finds satisfaction in solitary absorption mechanisms. This article introduces a successful method for creating PVA/NiFe2O4/(MoS2)x nanocomposites via a straightforward sol-gel technique, wherein porous amorphous NiFe2O4 microspheres are integrated into MoS2 nanosheets. The investigation uncovers that the incorporation of MoS2 results in an enhanced complex permittivity, facilitating the attainment of a desirable permittivity level. The PVA/NiFe2O4/(MoS2)x nanocomposites absorber exhibits an incredibly low reflection loss (RL) of -16.75 dB at a mere thickness of 1 mm, achieved through the cooperative interaction of dielectric and magnetic loss, along with the advantages of the structure and composition. Consequently, the PVA/NiFe2O4/(MoS2)x nanocomposites effectively absorb electromagnetic waves. Therefore, it is posited that MoS2-based composites hold great promise as highly effective microwave absorbers, boasting strong absorption intensity and a wide absorption frequency range, given the exceptional performance of the as-fabricated PVA/NiFe2O4/(MoS2)x nanocomposites.  

  olar observations have been of great importance not only to solar physicists but also to geologists, astronomers and meteorologists. The main source of energy for the earth is the sun, and changes in solar radiation and its composition have a significant effect on the weather and, consequently, human activities. Su  ots can be mentioned as one of the components that may affect meteorological parameters and the earth's climate system, which can ultimately cause fluctuations and changes in these quantities. In this study, by using different statistical methods such as correlation analysis, spectral analysis of time series and scatter plots, focusing on stations in the west of the country, which include 4 stations of Hamedan, Kermanshah, Khorram Abad and Sanandaj, in order to understand the possible effect of su  ots on the behavior of quantities Precipitation, average temperature, relative humidity and sea level pressure in the statistical period from 1979 to 2021 were calculated and the necessary investigation was done. The analysis of the correlation coefficient on the main data of meteorological quantities and su  ot data showed the absence of a significant linear relationship between them. But this does not mean the absence of other relationships between the changes of su  ots and meteorological parameters. Using other statistical methods such as drawing scatter diagrams, spectral analysis and filtering data in the band related to the 11-year cycle in determining the type of relationship between solar activities and meteorological quantities and also determining the intensity of its influence on this quantity. It was very effective. The peak related to the 11-year periodicity of su  ots and its intensity in different meteorological quantities were revealed using spectral analysis. From the data distribution charts, it was concluded that there is a weak relationship between the number of su  ots and the probability of light and heavy rain events, relative humidity and low and high temperature in the west of the country. In relation to the amount of pressure, no significant effect was observed.

  The Earth's atmosphere is a dynamic and complex gas covering that life on Earth depends on. With the entry of a large amount of gaseous and particulate pollutants into the earth's atmosphere, the air becomes polluted, and the reduction of air quality is harmful to humans and other living organisms. In the world, millions of people die due to air pollution, and 90% of them are in developed countries. Considering that the extreme dangers of pollutants are serious for all humans, but the vulnerability of some people to air pollution is much higher than others. Today, air pollutants have become a very important global issue because they are closely related to human health and environmental dynamics. One of the important pollutants that should be paid particular attention to is atmospheric suspended particles or particulate pollutants whose physical characteristics such as their concentration and size should be paid attention to. In this research, the average concentration of fine and coarse particles in the air has been investigated in different weather conditions and in different months and seasons in the period of 2015-1400. Also, the effect of meteorological parameters such as temperature, horizontal visibility, wind speed, precipitation and monthly changes curve and seasonal changes graph of each of the meteorological parameters and the average concentration of fine particles (PM2.5) i.e. suspended particles with an aerodynamic diameter of less than 2.5 micrometers and Coarse particles (PM10), i.e. suspended particles with an aerodynamic diameter of less than 10 micrometers, have been analyzed, and by obtaining the Pearson correlation coefficient, the degree of influence and direction of the relationship between meteorological parameters and particle concentration was obtained. The highest concentration of particles (PM10) has been observed in the summer season and the lowest concentration in the winter season. Also, the highest concentration of particles (PM2.5) was observed in spring and the lowest in winter. The results of the correlation analysis of meteorological parameters and suspended particles showed that the strongest correlation of PM10 with the temperature parameter has a direct relationship and then has an inverse relationship with precipitation. Also, the strongest correlation of PM2.5 with the wind speed parameter has a direct relationship.

Two-dimensional T-graphene is one of the allotropes of carbon, which is made of carbon tetragonal and octagonal rings alternately, and it is expected to have distinctive and interesting properties due to its different band structure compared to graphene. The electronic properties of nanostructures are a function of their geometry and type of atoms. In this thesis, an attempt is made to investigate the electronic properties of zigzag and armchair T-graphene nanotubes with different diameters. The theoretical approaches used are tight-binding approximation, nearest neighbor approximation and Green's function approach. For this purpose, we first write the Hamiltonian of the studied nanostructures in the tight-binding approximation and the second quantization for Bloch electrons without interaction, and then we obtain the equation of motion of the valence electrons of the considered system. In the next step, using the obtained Green's function, the density of energy states and band structure are calculated, and at the end, the graphs of band structure and density of energy states for zigzag and armchair T-graphene nanotubes has been drawn using coding in MATLAB programming language and we analyze the resulting graphs  

 Geophysical methods are one of the indirect methods for exploration that are widely used in the field of searching and exploring subsurface resources

اين مطالعه با هدف بررسي غلظت گرد و غبار در جو و واداشت تابشي هواويز­هاانجام گرفته است. براي اين منظور دو رويداد طوفان گرد و غبار رخ داده در 12 الي 14آوريل سال 2011 (23 الي 25 فروردين سال 1390) و 16 الي 18 ژوئن 2016 (27 الي 30خرداد 1395) با بررسي داده­هاي ديد افقي 18 ايستگاه همديدي در سه استان كردستان،كرمانشاه و ايلام واقع در غرب كشور ايران انتخاب شده است. براي انجام محاسبات وشبيه سازي­ها از مدل عددي WRF-Chem و طرحواره GOCART استفاده شده است. براي شرايط آغازين و شرايط مرزي در اين شبيهسازي، از داده­هاي باز تحليل GFS مراكز مليپيش بيني محيطي (NCEP) استفاده گرديده است. مدل تحت دو شرايط با درنظر گرفتن اثر گرد وغبار بر تابش و بدون در نظر گرفتن اين اثر اجرا شده است. براي ارزيابي نتايج حاصلاز مدل، داده­هاي ديد افقي گزارش شده از چهار ايستگاه از سازمان هواشناسي كشور، باغلظت شبيه سازي شده توسط مدل مقايسه شده و همچنين غلظت                                       اندازه­گيريشده در سازمان محيط زيست كرمانشاه با غلظت گرد و غبار شبيه سازي شده توسط مدلمقايسه شده است. نتايج نشان مي­دهد كهاين مدل در شبيه سازي طوفان­هاي گرد و غبار داراي عملكرد قابل قبولي است. نتايجحاصل از شبيه سازي با مدل WRF-Chem در دوحالت مدل سازي حاكي از آن است كه ذرات گرد و غبار با جذب و پخش تابش سبب كاهش تابشموج كوتاه و كاهش شار گرماي محسوس و نهان در سطح زمين در مناطق تحت تاثير گرد وغبار شده است. از ديگر اثرات اين ذرات، افزايش تابش موج بلند در سطح زمين و كاهشتابش زمين تاب در بخش فوقاني جو است.  

  Today, air pollution has become one of the serious concerns of humankind, and it has become more and more visible to the researchers and the owners of this science, since this disruption directly affects and affects human health. We know that suspended particles have a wide range of sizes and sources. In this study, the SMPS suspended particle measurement system was used to examine the particle size distribution in various environments.

  The Effect of Zagros Mountain Range on the Dust storm

  Abstract:Heat waves is one of environmental dangers which has got atmospheric origin and is of importance taking into account the effect it can have on the routine life and health of people as well as economy. In this research the synoptic analysis of heat waves in south west of Iran and the reason behind these waves, the exact statistics of these waves concerning continuity, intensity, time distribution and frequency have been studied. Also atmospheric circulation pattern in the time of heat waves and heat waves prediction by Markov model have been studied. In order to do so, data of maximum daily temperature of 15 synoptic weather stations in south west of Iran during 1990 to 2015 (26 years and 9496 days) were used. Then, after categorizing the data in excel, to identify heat waves percentile-derivation method was used, temperatures in proportion to 95 percentile or more were considered as heat waves. To identify heat waves of south west, temperatures which lasted for 2 days and occurred at 11 stations were defined as heat waves. Meanwhile 111 pervasive heat waves in the south west region were identified during 1990 to 2015 and were categorized as short-term, mid-term and long-term heat waves. The least-continuing waves were for 2 days and the most lasting ones for 17 days. Among these heat waves, four long-term heat waves were analyzed synoptically. After identifying heat waves and drawing frequency diagram and time distribution, the different maps related to different indexes of atmosphere (thickness, geopotential altitude of indexes: 850, 700, 500 hectopascal and wind speed vector at 850 hectopascal index) were drawn. Studying maps shows that a thermal low-pressure at ground level and tidal high pressure deployment in middle layers of atmosphere lead to weather stability and temperature intensity. Then by using Markov model and getting transfer status frequency matrix (N) and transfer status probability matrix (P) and by using Markov model as well as R software and installing Markov package in this software, heat waves become predictable for coming years.     

تحليل و بررسي روند تغييرات پنج آلاينده معيار آلودگي هوا در شهر كرمانشاه در سال هاي 1393-1384

Air pollution is one of the most important recent environmental problems which is the presence of gaseous, liquid, and solid compounds or a mixture of them in the air. Therefore; it can endanger human health directly or indirectly and it also causes harm to animals, plants, buildings and bodies.  The main air pollutants include particulate matters and gases. Particulate matters are solid or liquid particles that are suspended in a gas (usually air). Since particulate matter pollutant nowadays have become a critical pollutant of metropolises , the evaluating of particulate matters concentration in indoor and outdoor environments in Kermanshah province has became necessary. The results of extensive studies on indoor air pollution indicate that the effect of air pollution in indoor environments is more than air pollution in urban environments, as most people in the urban community spend about 80% to 90% of work and life time in indoor environments and are exposed to air pollution in these environments. As a result, this study aimed at investigating significant indoor pollutants, their sources and their effects on health, the introduction of some of the indoor pollutants resources and the study of the limitations of indoor pollutants in the world as well as Iran. As Kermanshah province is the second province that is involved with the dust storm, and the quality of indoor air is influenced by out, this study examined the indoor air quality using Lighthouse HANDHELD 3016 Particle Counter under dusty and clean conditions, in the environments equipped with water and gas air conditioners over 5 minute periods (22 time cycles).  The results of the research showed that in all measurements, the particles with the diameter of 0.3, 0.5 and 1 micron had the most frequency, respectively. Also, as particles with a diameter of more than 1 micron (very large particles) can enter the atmosphere through dust, by making comparison between the number of particles with a diameter greater than 1 micron in the indoor environments equipped with water and gas air conditioners under dusty and clean conditions, it was found that these particles in dust conditions in environments with water conditioners increased up to 3 times in some cases than those in gas air conditioners. That is to say, water air conditioners bring much more dust particles into indoor environments. Regarding various studies, photocopiers and printers can be considered as an important source of particulate matters (ultrafine and fine particles) in office environments. In order to investigate this, the concentration of particles 0.3, 0.5, 1, 5, and 10 micrometers in diameter was measured before the devices were turned on, as well as during the operation of the machines in the printing office with the largest number of photocopiers and printers in Kermanshah province. The results showed a significant increase in the concentration of 0.3, 0.5 and 1 micron particles, fine mode, during the printing process in the printing office air.

Today in Iran, air pollution is the first issue of environmental pollution and urban tra  ortation system is the one of the main causes its release, Aerosols and gases are the most important known pollutants in the air. Air pollution has many reasons in different cities of Iran such as increase traffic, deforestation, forest fires, increased establishment of factories and power plant, natural factors such as dust storms. Pollution of geo graphical environments in Iran by Aerosols and gases is one of the most important issues in this country. Air pollution has 2 type of pollutant: a) Particle   b) Gas , particularly   there are Jobs and various industrial activities that produce this pollutants. Therefore, measurement of this pollutants is very important because they are effective on health and environmental degradation, Therefore, we must use efficient methods for reduce the concentration this pollutants.In this study, after a brief review of air pollution;, in summary, we defined air pollution, then, we   measured Aerosol   with Cascade Impactor 8 stages and i   the next step, we analyzed   the physical and chemical data in different places of Kermanshah city. In determining the chemical composition, results show that among the five elements V, Cr, Hg, Cd and pb, Hg has the highest mass. In determining the Aerosol size distribution, results show that in Dust storm and Urban traffic the most particles are in the range of Coarse Mode and Accumulation Mode. In the next section, we defined concentration of gaseous pollutants in different places of Kermanshah city , results show that printer home produces O3 and NO2 and heavy traffic produces CO,CH4,Ben and NOx. At the end, the ways have been suggested for reduction of air pollution.