نتایج جستجو برای: سامانه 137
تعداد نتایج: 22285 فیلتر نتایج به سال:
فرسایش آبی به عنوان یکی از عوامل مؤثر بر تخریب خاک به شمار میآید. برای محاسبۀ فرسایش خاک تقریبی مدلهای تجربی و نظری زیادی توسعه یافتهاند. سزیُم 137 در مطالعات فرسایش خاک در بسیاری از مناطق مختلف جهان، به عنوان یک فناوری جدید و دقیق استفاده میشود. ضرورت استفاده از این فناوری، انتخاب و استفاده از مدل تبدیل مناسب برای برآورد بهتر میزان فرسایش و رسوب است. به دلیل کمبود منابع فارسی در زمینۀ مدل...
پرتوهای یون ساز می توانند آثار دائمی یا موقت بر عملکرد مدارهای الکترونیکی داشته باشند. آثار موقت که در حین تابش دهی ظاهر شوند، می توان به عنوان نشانه ای از وجود پرتو یون ساز در محیط دانست که برای آشکارسازی پرتو یون ساز مفید هستند. در این مطالعه، اثر فوتون های گاما بر جریان معکوس دیود در حالت بایاس معکوس و مقایسۀ آن با همان جریان در حالت بدون تابش مورد بررسی قرار گرفت تا از این طریق، امکان به کا...
Pyrococcus abyssi virus 1 (PAV1) was the first virus particle infecting a hyperthermophilic Euryarchaeota (Pyrococcus abyssi strain GE23) that has been isolated and characterized. It is lemon shaped and is decorated with a short fibered tail. PAV1 morphologically resembles the fusiform members of the family Fuselloviridae or the genus Salterprovirus. The 18 kb dsDNA genome of PAV1 contains 25 p...
The use of brachytherapy sources in radiation oncology requires their proper calibration to guarantee the correctness of the dose delivered to the treatment volume of a patient. One of the elements to take into account in the dose calculation formalism is the non-uniformity of the photon fluence due to the beam divergence that causes a steep dose gradient near the source. The correction factors...
During Chernobyl accident a large amount of radionuclides were released into atmosphere and added to atmospheric nuclide inventory from weapons tests. In early May of 1986 in South Korea, radioactivities such as 1-131 and Cs-137 were detected in surface air and rain water. That indicated that Chernobyl debris spreaded to far eastern Asia. In the present time, the long-lived radionuclides have b...
1175 PERSPECTIVES M ost of us use the Internet to exchange information in everyday life. The ever-increasing rate at which Internet connections transmit data requires faster and faster conversion of local information into signals that can be easily transmitted over long distances. For example , the information sent by your computer is converted from electronic signals into optical signals, whic...
The reactor accident at Chernobyl on 26 April 1986 dramatically demonstrated the dangers involved in man-made radioactivity. The Chernobyl catastrophe was incomparably larger than the reactor accident in Harrisburg, USA in 1979. Chernobyl released enormous amounts of radioactive substances. Wind and weather dynamics transported these substances and deposited them onto the earth as radioactive d...
In Japan, where all cell concentrates are irradiated because of an unusually high risk of transfusion-associated graft-versus-host disease (GVHD) due to the high percentage of HLA homozygous subjects in the population, there have been problems with the breakdown of IBL gamma irradiators. When an irradiator breaks down, it is often found to be difficult for the agencies, or even the manufacturer...
OBJECTIVES We aimed to assess the radiation exposure for epidemiologic investigation in residents exposed to radiation from roads that were accidentally found to be contaminated with radioactive cesium-137 ((137)Cs) in Seoul. METHODS Using information regarding the frequency and duration of passing via the (137)Cs contaminated roads or residing/working near the roads from the questionnaires t...
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