نتایج جستجو برای: helium
تعداد نتایج: 14695 فیلتر نتایج به سال:
One of the most appropriate methods for elimination of trace impurities in helium is cryogenic adsorption process. So, in this study design and construction of cryogenic adsorption helium purification system (3 Nm3.hr-1, 80 bar) carried out using activated carbon as adsorbent at 77K. To evaluation of adsorption dynamics and effect of pressure on elimination of trace impurities, helium purificat...
Damage of tungsten due to helium and argon ions of a PF device was studied. Tungsten samples were irradiated by 20 shots of the plasma focus device with argon and helium as working gases, separately. The tungsten surface was analyzed by SEM, before and after irradiation. SEM revealed dense blisters with diameters of a few hundred nanometers, on the samples which were irradiated by helium ions, ...
چکیده ندارد.
Optically pumped helium magnetometers are important instruments whichhave many applications in military, mass spectroscopy and space applications. In thispaper, the working principles of helium magnetometers have been explained. There isalso an introduction of a new method for finding the resonant frequency, which hasadvantages to the typical method such as more sample r...
In this paper, the laser ablation process based on the irradiation of nanosecond pulsed lasers on a copper target surface in the presence of Helium gas is studied. The dynamical behaviors of the generated plasma in the helium gas and evaporated copper at the atmospheric pressure are examined using a laser pulse, laser wavelength of and intensity of 7×1010W/cm2. A one-dimensional thermal model ...
Introduction: Several studies have discussed to the electron contamination caused by the air column between the head of linac and patient for photon beams. Since it is not possible to measure the electron contamination with practical dosimetry, the Monte Carlo technique is an appropriate and accurate choice to calculate particle flounce in radiation therapy. The purpose of t...
Metastable atomic and molecular helium anions exhibiting high-spin quartet configurations can be produced in helium droplets via electron impact. Their lifetimes allow detection in mass spectrometric experiments. Formation of atomic helium anions comprises collision-induced excitation of ground state helium and concomitant electron capture. Yet the formation of molecular helium anions in helium...
The Stirling Cycle is one of the thermodynamic cycles that is close to Carnot cycle in term of theory, and these advantages cause to using Stirling engines in wide industries. The main objective of this research is experimental investigation of Stirling Gamma engine for refrigeration. In this investigation, effect of working fluid air and helium, operatring pressure of working fluid and dynamo ...
Helium droplets provide the possibility to study phenomena at the very low temperatures at which quantum mechanical effects are more pronounced and fewer quantum states have significant occupation probabilities. Understanding the migration of either positive or negative charges in liquid helium is essential to comprehend charge-induced processes in molecular systems embedded in helium droplets....
As an illustration, consider the following two-step adsorption cycle to purify helium diving gas. Helium diving gas is principally a mixture of oxygen and helium, when the diving chambers are depressurised, the contaminated gas will consist mainly of carbon dioxide, oxygen and helium. Traditionally this waste gas has been thrown away. The PSA cycle described below is a method of purifying this ...
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