Sharif Digital Repository

There is a growing interest in developing high-performance sensors monitoring fungicides, due to their broadly usage and their adverse effects on humans and wildlife. In the present study, a colorimetric probe has been proposed for detection of prothioconazole based on aggregation of unmodified silver nanoparticles (AgNPs). Under optimized condition, linear relationships between the concentration of prothioconazole and the absorbance ratio of A500/A395 were found over the range of 0.01 µg. mL-1 to 0.4 µg. mL-1 with Detection limit as low as 1.7 ng. mL-1. Furthermore, AgNPs color change from yellow to pink-orange in presence of prothioconazole, indicates highly sensitive naked-eye... 

In the first part of this research, a single-component colorimetric sensor array based on the aggregation of AuNPs has been designed for the quantification and classification of antidepressant drugs (fluvoxamine (Flu), nortriptyline (Nor), citalopram (Cit), alprazolam (Alp), diazpam (Dia), sertraline (Ser), zolpidem (Zol), and imipramine (Imi)). Tuning the pH and ionic strength enabled the single-component probe to interact with the target analytes through different binding modes, providing the required cross-reactivity. To generate the array, a single AuNP was embedded into six experimental conditions: three different buffers (acidic, neutral and basic) each at two concentration levels (1mM... 

In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon... 

Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic... 

To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have... 

Ultrafast signal processing in time-domain with high resolution and reconfigura-bility is a challenging task. This paper, for the first time, introduces a time-varying metasurface consisting of graphene microribbon array for implementing time-lens in the terahertz domain. Given that the surface conductivity of graphene is proportional to the Fermi energy level in the THz regime, it is possible to change the phase property of the incident electromagnetic pulse by changing the Fermi level while the Fermi level itself is a function of voltage. Upon this fact, a quadratic temporal phase modulator, namely time-lens has been realized. This phase modulation is applied to the impinging signal in the... 

In this research, the problem of locating fire stations and allocating equipment has been studied and a simulation-optimization approach has been presented to solve the problem. The mathematical models of this research were developed based on the idea of the randomness of the covered demand and the maximum expected coverage model. In these models, the issue of non-availability of equipment to cover accidents, the random nature of accidents, various fire incidents and the equipment needed to cover them are considered. Two mathematical models with deterministic and non-deterministic approach with different scenarios for demand are proposed. The non-deterministic model is developed with the aim... 

One of the main concerns of industrial companies’ managers is providing an efficient logistics system. To achieve an efficient logistics system, the fleet planning problem is studied by many researchers in recent years. This problem consists of multiple sub-problems at three levels: operational, tactical, and strategic. These sub-problems are closely related to each other and need to be studied and addressed in an integrated manner. In this research, an attempt is made to provide an integrated framework to solve the vehicle routing problem (operational), outsourcing problem (tactical), and fleet composition problem (strategic). These problems have various uncertainties, including customer... 

The Use of peer-to-peer architectures instead of traditional client-server architecture can be beneficial in many aspects such as increasing scalability of the systems, enhancing fault tolerance in critical situations, extending the system resources and various other advantages. Nowadays, many applications are based on peer-to-peer architectures and as a result, a large portion of the internet traffic is produced by these applications. This has been a motivation to many researchers to focus on reducing the amount of this traffic while satisfying the content distribution demands. One of the main problems that can result in generating large amount of traffic and also long response times for... 

In today’s competitive world، web services have become more and more prevalent and their efficient discovery and composition in order to create novel functionalities is essential for variety of applications. Due to the large number of available services، the discovery of services is a difficult and time consuming task. Existing approaches in web services discovery and composition attempt to use simple web services while ignoring the use of once composed services. Reusing frequently used composite services can considerably increase performance of the entire system. Moreover، the advent of semantic web، as an effective solution of representing information interpretable by machines and none... 

Nowadays, the essentiality of appropriate modeling languages has become evident, and with the introduction of new concepts such as domain-specific languages, the need for systematic research on designing and engineering new modeling languages has increased significantly. Several modeling languages have been developed and employed over the years, but the area of modeling languages still suffers from the lack of a proper framework: There is a strong need for an engineering framework that specifies the detailed steps of language development, the input and output artifacts of each step, the techniques applicable to each step, and quantifiable methods for quality measurement. From a unified point... 

Peer-to-peer (P2P) computing is a popular distributed computing paradigm for many applications which in-volve exchange of information among a large number of peers. In such applications, large amount of data is distributed among multiple dispersed sources. Therefore, data analysis is challenging due to processing, storage and transmission costs. Moreover, the data rarely remains static and frequent data changes, quickly out date previously extracted data mining models. Distributed data mining deals with the problem of data analysis in environments with distributed data and computing resources. In this dissertation, we explore distributed data mining in different structures of P2P systems. In...