front end یک رادار باند (f=9.4ghz)x به صورت (microwave integrated circuits)mic طراحی، ساخته و اندازه گیری شد . تقویت کننده کم نویز مدار یک تقویت کننده بالانس می باشد که ترانزیستورهای آن gaasmesfet به صورت چپ می باشند. بهره تقویت کننده در فرکانس 9.4ghz برابر 13db و عدد نویز آن 3db اندازه گیری می باشد . میکسر مدار، یک میکسر دیودی به صورت تک بالانس بوده و هایبرید 180 درجه آن از نوع حلقه (ratrace) ...

Abstract: Background and aims: Using water pump in residential buildings to provide the required water pressure is accompanied by noise pollution and the annoyance of residents. So, the purpose of this study is to reduce water pump noise pollution with designed acoustic curtains in a residential building of Qazvin city.   Methods: The mean sound pressure level was measured before and ...

  Background and aims   Overexposure to industrial noise pollution induce hearing loss workers. Occupational hearing loss may cause interference whit oral communication, so it may  increase the risk of occupational accidents in workplace as well as affects whit social activities.  This study was conducted on Lavan Island, are of oil extracting regions in the south of Iran. The  object of this s...

This research proposes the effect of temperature variation in the Prandtl number on the power, the efficiency and the heat loss of the Gama-type Stirling engine. It should be noted that the Prandtl number included the viscosity, the thermal conductivity coefficient and the specific heat at constant pressures of the working fluid, which the temperature dependency of such first two thermo-dynamic...

Background: Sinus surgeries are usually associated with bleeding, thus can result in hemodynamic instability. This study investigated the hemodynamic changes induced by remifentanil plus isoflurane administration in comparison with propofol plus remifentanil in patients undergoing sinus surgery.Methods: In this randomized clinical trial study, 96 patients were divided into two groups of isofl...

Introduction: Working in noisy environments may cause hearing loss. Studies have shown that some factors along with noise are independently involved in hearing loss, one of which is cigarette smoking. The aim of this study was to evaluate the effects of smoking on hearing loss in workers exposed to occupational noise. Materials and Methods: The workers’ hearing loss was measured through a tona...