نتایج جستجو برای: shielding gas
تعداد نتایج: 253666 فیلتر نتایج به سال:
Sensing plays a key role in automating and controlling welding processes. Although arc light sensing has advantages over through-the-arc sensing for arc length control and seam tracking, the current technology relies on experimental data and lacks theoretical foundation. To improve measurement accuracy, this work addresses the theoretical foundation for arc light sensing. A theoretical model ha...
The physical and chemical properties of Pyrazole and Pyrazoline molecules were theoreticallystudied by Gaussian 03, software with NMR and Molecular orbital calculations at B3LYP/6-31G andB3LYP/6-31+G(d) levels, in gas phase and solution. In this study a comparison effect of threesolvents with different dielectric constants on Pyrazole and Pyrazoline molecules in aspect energyinteraction between...
The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of (1)H(35)Cl are CCl = ...
A synchrotron radiation (SR) facility typically consists of an injector, a storage ring, and SR beamlines. The latter two features are unique to SR facilities, when compared to other types of accelerator facilities. The SR facilities have the characteristics of low injection beam power, but high stored beam power. The storage ring is generally above ground with people occupying the experimental...
Oxygen-isotope composition of the solar wind returned by GENESIS indicates that the Sun is 16 O-rich (Δ 17 O SMOW = −26±6‰) [1], supporting one of predictions of the CO self-shielding models [2−4]. The self-shielding models [3,4] assume that both the solids and gas were similarly 16 O-rich (Δ 17 O ~ −25‰), and solids subsequently evolved towards the terrestrial value as a result of CO self-shie...
In this research, Quantum-mechanical calculations were performed at the HF method with the 6-31+G*basis set and at the B3LYP method with the 6-31+G* basis set in the gas phase and five solvents such as water, DMSO, methanol, ethanol and dichloromethane at six temperatures. According to these theoretical results of IR, we extracted thermo chemical parameters such as enthalpy (∆H Kcal/mol), Gibbs...
Density functional theory methods(DFT) and natural bond orbital (NBO) analysis were used to investigate the effects of isomerism and side chain mutation at a microscopic level on the stability, binding energy and NMR/NQR tensors of structural isomers, L- methionylasparagine (Met-Asn) and L- asparagylmethionine (Asn-Met) in the gas phase. The results represented that the isomerism and side chain...
From the point of view of radiation safety, interstellar space is not empty. Neutral and ionized interstellar gas and cosmic rays consisting of H and He-nucleons constitute radiation hazard aboard relativistic interstellar ships. Relativistic aberration of cosmic rays is evaluated and radiation doses from oncoming relativistic flow of interstellar gas and cosmic rays are estimated. Necessary sh...
The ablation rate expressed as the amount of removed material per laser shot was calculated for pure metal samples under different experimental conditions: laser fluence (1.3–16.7 J cm−2), buffer gas (air, He and Ar) and gas pressure (103 –10−5 mbar). Fluence values covered the range between the plasma threshold (~1–2 J cm−2 for most elements) and 16.7 J cm−2. The 581 nm output of an excimer-pu...
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