فصلنامه فناوری آموزش
پیاپی 3 (تابستان 1386)

Theories of linear stability, reinforcement, or degradation of small disturbances examine the velocity applied to the average velocity of the flow. When the boundary layer flow expands linearly in the early stages of its development, the input boundary conditions of the computational domain are determined using the results of the linear stability solution. In order to better adapt to laboratory results, spatial stability analysis is used. Using an algebraic mapping, the physical domain is converted to a computational domain. To solve the Or-Samerfeld equation, a spectral method has been used that has led to the solution of a special value problem. Comparing laboratory results and results of spatial and temporal perturbation stability analysis, it can be stated that spatial perturbation growth analysis more accurately describes the instability characteristics of the perturbation boundary flow. Small frequencies are much more accurate.

The use of a hysteresis motor in precision systems, such as inertial navigation and video recorders, requires rapid dynamics and precise control of the motor. The control system is a closed loop control system that speeds up the system's response speed, and in fact using it, alternating current motors are considered as a permanent current motor. Permanent flow motors are used in many applications that require precise control and rapid dynamic response. However, due to the many disadvantages of DC motors, such as high maintenance costs; The use of AC motors has been considered in drive systems. Therefore, the vector control method has also been used to improve the performance of AC motors. In this paper, the dynamic behavior of conventional hysteresis motor based on the two-axis model of d-q is examined and then its vector control system is simulated. In addition, the variables d and q are well separated and independently controlled using the feedback method. The results of the paper show that the use of this control method has had a significant effect on the dynamic increase of the system.

Most existing regulations, unlike cutting, do not provide for reinforced concrete reinforcement for reinforced concrete members after cracking. In this paper, the torsional strength of reinforced concrete beams with longitudinal and non-silent reinforcement is modeled and examined during and after cracking. This modeling is based on ANSYS software, which is based on finite element theory. The results of the modeling have been compared with the laboratory results. These results are consistent with the results of experiments and show that there is a residual complexity of the residue in concrete beams reinforced with longitudinal reinforcement alone.

In this paper, we first simulate ML, MUSIC, Root-MUSIC algorithms and space smoothing in noisy and fiddling environments, and then these algorithms are compared in terms of estimating the accuracy of the angles received from the two sources. By presenting the simulation results of four algorithms in the form of tables that are based on mean, deviation from mean, variance of estimated angles and the percentage of successful experiments, it is observed that Root-MUSIC and MUSIC algorithms in terms of estimation and Detecting close angles is more accurate. In these two methods, the angles close to each other, up to about one degree, can be detected and separated. In addition, simulation results show that spatial smoothing algorithm is the most effective way to identify coherent resources.

Euclidean geometry has been taught to students in schools for many years. Topological structures are among the topics that have not received much attention in school geometry. The knot is one of the most suitable topics for teaching in school, which has a topological structure. In addition to being rooted in human culture and experience, knots are a theoretical and practical field in mathematics, physics, biology, and chemistry. In this article, after a brief acquaintance with the nodes, an explanation for the title "Geometry of nodes" is given. In the first part of the article, in the first part, the reasons and analyzes for the selection of nodes and the importance of teaching it in school are explained, and in the second part, a proposed plan for teaching knot geometry to students is briefly presented. Experimental implementation of this project, in which one group of elementary school students and the other group including students from the third year of middle school and the first year of high school participated, has had satisfactory initial results.

The historical study of developed countries and their economic and industrial prosperity shows the serious attention of managers and planners of these countries to standardization in education. The education system of a country is the most vital part of the economy and the most popular institution for the state. In the United States, the report "A Dangerous Nation" was published and an alarm was sounded. In Science for All Americans, he published both a national slogan and strategies for teaching science. Then, the concept of "scientific literacy" was published in full detail and the report "Fundamentals and Strategies for Transformation". At that time, all those involved and consumers of science education were convinced that change was both necessary and inevitable. Eventually, all of these activities led to the development of an important work, "Science Education Standards." With the introduction of standards, important recommendations for change or transformation were proposed, such as "change of emphasis" - using all this information and using the principles of scientific research learning, to create a broad and massive change in the teaching of Iranian science, infrastructure proposals and In addition, we have provided an applicable and important one - we hope that this article will be of interest to decision makers of science education at the national level and as soon as possible with a great effort and with the cooperation of all classes, especially teachers and researchers and specialists in science education. , To see the change of science education standards in Iran.

The aim of this paper is to provide a link between research projects and education to optimize teaching and learning of related subjects. In a research project, three compounds including an intermolecular proton transfer compound, a hydrated carboxylic acid, and a metallic complex were synthesized, all of them have non-covalent interactions such as O−H∙∙∙O, O−H∙∙∙N and C−H∙∙∙O hydrogen bonds as well as van der Waals forces and π-π stacking resulting to different supramolecular structures. The structures of compounds are characterized by single crystal X-ray diffraction method. The classic concepts and definitions related to the subject are given in the last section.