Sharif Digital Repository

E-plane waveguide filters are good choices due to highly manfacturing accuracy in Q-band microwave devices.To increase the attenuation slop or selectivity of such filters one need to synthesis transmission zeros with cross coupled resonators.With this method for constanst degree and return loss, attenuation slop increases in comparison to direct coupled resonators.
In this thesis we designed and fabricated a Q-band 4th degree filter,with center frequency at 42.1746 GHz and bandwidth of 350 MHz with two transmission zeros. Results of simulations and measurments are given in chapters 3 and 5.
Microwave filters using coupled resonators are important components in microwave systems.... 

In the last two decades, Convolutional Neural Networks (CNN) have shown significant capabilities in artificial intelligence. These networks are able to provide comprehensive conclusions about the overall behavior a system by analyzing the relationship between the components of that system; Clearly, these networks have been successful in performing categorization tasks. However, there are no coherent theories as to why they work, and how to optimize them. On the other hand, according to recent research on the relationship between deep networks (in computer science) and Renormalization Group (in physics), convolutional networks seem to use a method similar to the Density Matrix Renormalization... 

The so called T(b) theorem for boundedness of generalized CalderonZygmund singular integrals is investigated. This theorem provides a criterion, in which boundedness of the operator is equivalent to a special condition for the image of some function under action of that operator.Then we discuss some applications of the theorem in analysis and partial differential equations  

global warming and air pollution due to the excessive consumption of fossil fuels have led to the proliferation of renewable energy sources (RESs). RESs are connected to the grid through power electronic converters and therefore, provide insignificant inertia and damping property for the system. As a result, the system overall inertia and damping is decreased and therefore, the system stability is jeopardized. This thesis presents a comprehensive small signal model for a virtual synchronous generator (VSG) integrated into a microgrid. In the developed state space, active and reactive power control loops of the VSG as well as resistances and reactances of the lines are considered. Based on... 

Financial benefits are no longer the only decision makers’ criteria and they consider environmental and social merits due to the modern nature of management and international competing. As a result, sustainable supply chain management (SSCM) rises noticeably in popularity among academics for researching on it and industrialists for applying it. Having reviewed respective researches, The SSCM is addressed by an integrated approach in this rsearch for selecting green suppliers and finding optimal production plan in two phase. In first phase, thank to related literature, a framework including environmental criteria is purposed for evaluating suppliers by Analytic network process method (ANP).... 

The purpose of this research is to develop a contactless angular sensor based on magnetic methods that in addition to having similar outputs to resistive angle sensors (contact potentiometers) has advantages such as longer lifetime and no sensitivity to contamination, moisture and dust. In this research, an angular GMR sensor is designed and manufactured and tries to present a product that meets the required standards and can be sold in domestic and foreign markets  

In this investigation, cellular structure of a weakly unstable detonation wave in H2/O2/Ar mixture is studied. The detonation is simulated using 2D reactive Euler equations and one step Arrhenius type reaction model developed by Mr. Barkhordari. The numerical technique is the high order Piecewise Parabolic Method on the basis of Godonov method. The numerical fluxes are computed based on a high-order extension of the Godunov's method; the piecewise parabolic method (PPM). The initial cell formation processes and different machanisms involved in cell size changes are studied. This study shows that the form of initial perturbation used to intrigate the instability of detonation is not important... 

A lot of researchers have suggested that ostracism as a disruptive behavior, has been widespread among organizations and a lot of researches has been studied its consequences in recent years.This research studies ostracism’s consequences and proposes a theoretical model of organizational ostracism with affective commitment, intention to turnover and organizational dependability as one of affective commitment’s antecedents. This study has been done on 231 employees of three medium knowledge-based organizations to identify the effects of ostracism on employee’s turnover behavior. Results show that ostracism, due to its impact on the affective commitment of ostracized peoples, reduces this type... 

Purpose: The purpose of this thesis was to identify active followership behaviors of followers in interaction with autocratic leaders. An active follower thinks critically and takes initiatives.
Design: Given that Followership literature is still in its infancy, the research questions needed a qualitative approach, in this case grounded theory. In total, 19 top- & middle-level managers were interviewed as leaders and followers, accordingly, using semi-structured interviews.
Findings: 4 categories of active followership were found, each having 3-4 specific behaviors. These categories are: precautionary behaviors, facilitating behaviors, modificating behaviors, and consolidating... 

There is no consensus definition of cynicism in literature. In this research different definitions of cynicism have been investigated and two concept of organizational cynicism and trait cynicism have been taken into consideration. Organizational cynicism is a negative attitude that is prevalent in employees. In literature some antecedents and consequences of organizational cynicism have been suggested. It seems organizational cynicism can be investigated in a more complex relations. The focus of this research is on the mediating role of organizational cynicism on the likely relations between politics perception and organizational commitment. That is to say organizational cynicism can... 

Feedback-seeking behavior is the effort of employees to get feedback from the environment and around people about their performance. One of the research questions in this field is about the factors that increase this behavior in the staff. Transformational leadership as a leadership style, stimulates, and motivates followers to achieving desirable operational results. In addition, an important consequence of this style could be increasing the followers' capabilities. Transformational leaders are trying to empower their followers to build and empower them, which can provide a strong incentive for employees to move and grow, which may encourage them to have a better performance. One of... 

Although existing literature on organizational culture and its change process contains meaningful and rich theories but our studies show that there is no perfect and detailed framework on linking organizational culture change and corporate entrepreneurship culture. In addition to that, Gamification –defined as taking the game design elements into non-game contexts– is a fruitful and academically rich research area. Fortunately an idea proposed recently to explain a method for enhancements in organizational culture in general, and in corporate entrepreneurship culture in particularby Yavari and Jafarian based on using game mechanisms. In their paper "A Gamification-Based Method for Corporate... 

Considering the importance of biocompatibility of implantable prothesis’, metallic alloys have weaker corrosion resistance than ceramics. In order to extend usage of nanomaterials to improve the bio-properties of materials, Nano-structured ceramic coatings are being suggested to improve corrosion resistance and biocompatibility of prosthesis. Meanwhile, very good properties of TiN, such as corrosion resistance and mechanical properties as a thin film coating are undeniable. In this study, TiN and Ti2N thin film were deposited on Ti-based substrate, using PVD and Magnetron sputtering at different argon to nitrogen ratio. The crystal structure of the films was examined using Grazing XRD... 

There are several methods proposed for the instruction and assessment of interlanguage pragmatic competence of foreign language learners. Dynamic assessment as one of the recent methods arising from Vygotsky’s sociocultural theory of mind incorporates assessment and instruction by engaging learners in a process of interaction with the mediator while the learners are trying to perform a challenging task. The present study aimed to explore the advantage of Dynamic Assessment as an instructional instrument over the Non-dynamic (traditional) Assessment and Non-assessment approaches and their effects on the Iranian intermediate level students. The target speech acts of apology, complaint, and... 

Fiber optic sensors have found industrial applications due to their unique characteristics and wide range of environmental parameters. Specifically, distributed optical fiber sensors which have applications in borders protection, intrusion detection, oil and gas leakage detection and smart irrigation of farms and gardens, have attracted significant attention from research groups around the world in recent years. According to the forecasts, among all kind of optical fiber sensors, the temperature and acoustic/vibration sensors will seize the market during the coming years. In this thesis, three kind of optical fiber sensors are proposed for environment health monitoring. First, distributed... 

Industrial enzymes can generally be classified into three groups: carbohydrases, proteases and lipases, which account for a major part of the global enzyme trade. Proteases, in particular, have always been extensively studied and investigated due to their widespread use in various industries, such as food, pharmaceutical, chemical, and agricultural sectors. Proteases are a group of proteolytic enzymes that break down proteins and peptides into their constituent amino acids by hydrolyzing peptide bonds. Among the family of proteases, alkaline serine proteases have special biocatalytic abilities in both aqueous and organic environments. Their suitable resistance in alkaline environments and... 

The accurate assessment of biomarkers likes proteins, hormones or other biomolecules that amount of them changes with state of disease or level of treatment and gives diagnostic information is a difficult duty. In these samples, pathogens exist in small quantity compared to other background molecules. Therefore, appropriate sampling process for concentrating and separating pathogens from the matrix should be developed in order to provide rapid and accurate pathogen detection test. In this thesis design and fabrication of microfluidic biosensors based on the modified nanofibrous membranes were investigated and explained. PES nanofibrous membrane with carboxyl functional groups for covalent...