ترغب بنشر مسار تعليمي؟ اضغط هنا

Comparison of deuterium retention in tungsten exposed to deuterium plasma and gas

63   0   0.0 ( 0 )
 نشر من قبل Xiaoqiu Ye
 تاريخ النشر 2019
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Deuterium(D) retention behavior in tungsten(W) exposed to deuterium plasma and gas was studied by means of thermal desorption spectroscopy (TDS): deuterium plasma exposure in which W was exposed to D plamsa with 35 eV/D at 393 K to the fluence of 3.8E24 D/m2; D2 gas charging in which W was exposed to D2 gas of 500 kPa at 773 K for 4 hours. TDS shows that the total D retention in plasma exposure W is 1.00E22 D/m2, one order of magnitude higher than that of gas charging W; however, the D2 desorption peak of gas charging W is 952 K, much higher than 691 K of plasma exposure W. The detrapping energies of deuterium were determined experimentally from the measured peak temperatures at different heating rates and were found to be 2.17 eV for gas charging W and 1.04 eV for plasma exposure W, respectively.



قيم البحث

اقرأ أيضاً

Understanding the retention and recycling of hydrogen isotopes in liquid metal plasma-facing materials such as liquid Li, Sn, and Li-Sn are of fundamental importance in designing magnetically confined fusion reactors. We perform first-principles mole cules dynamics simulations of liquid Li-Sn slab with inserted D atoms to provide microscopic insights into the interactions of D with Li-Sn liquid metal. We observe evaporation of D$_2$ and LiD molecules out of the Li-Sn slabs. With detailed analysis, we unveil a cooperative process of forming D$_2$ molecules in liquid Li-Sn, where Li atoms act as catalytic centers to trap a D atom before another D comes nearby to form a molecule, and the surplus charges are transferred from D$_2$ to nearby Sn atoms. Furthermore, we predict a temperature window in which D$_2$ molecules can escape to vacuum, while LiD molecules cannot. The above findings deepen our understanding of interactions between hydrogen isotopes and Li-Sn liquid metal.
Combining spatially resolved X-ray Laue diffraction with atomic-scale simulations, we observe how ion-irradiated tungsten undergoes a series of non-linear structural transformations with increasing irradiation exposure. Nanoscale defect-induced defor mations accumulating above 0.02 displacements per atom (dpa) lead to highly fluctuating strains at ~0.1 dpa, collapsing into a driven quasi-steady structural state above ~1 dpa. The driven asymptotic state is characterized by finely dispersed vacancy defects coexisting with an extended dislocation network, and exhibits positive volumetric swelling due to the creation of new crystallographic planes through self-interstitial coalescence, but negative lattice strain.
107 - D. Galli , F. Palla 2002
We review and update some aspects of deuterium chemistry in the post-recombination Universe with particular emphasis on the formation and destruction of HD. We examine in detail the available theoretical and experimental data for the leading reaction s of deuterium chemistry and we highlight the areas where improvements in the determination of rate coefficients are necessary to reduce the remaining uncertainties. We discuss the cooling properties of HD and the modifications to the standard cooling function introduced by the presence of the cosmological radiation field. Finally, we consider the effects of deuterium chemistry on the dynamical collapse of primordial clouds in a simple ``top-hat scenario, and we speculate on the minimum mass a cloud must have in order to be able to cool in a Hubble time.
126 - Hanyu Liu , Yanming Ma 2012
The recent discovery of phase IV of solid hydrogen and deuterium consisting of two alternate layers of graphenelike three-molecule rings and unbound H2 molecules have generated great interests. However, vibrational nature of phase IV remains poorly u nderstood. Here, we report a peculiar proton transfer and a simultaneous rotation of three molecule rings in graphenelike layers predicted by ab initio variable cell molecular dynamics simulations for phase IV of solid hydrogen and deuterium at pressure ranges of from 250 to 350 GPa and temperature range of from 300 to 500 K. This proton transfer is intimately related to the particular elongation of molecules in graphenelike layers, and it becomes more pronounced with increasing pressure at the course of larger elongation of molecules. As the consequence of proton transfer, hydrogen molecules in graphenelike layers are short lived and hydrogen vibration is strongly anharmonic. Our findings provide direct explanations on the observed abrupt increase of Raman width at the formation of phase IV and its large increase with pressure.
Supersolid is a mysterious and puzzling state of matter whose possible existence has stirred a vigorous debate among physicists for over 60 years. Its elusive nature stems from the coexistence of two seemingly contradicting properties, long-range ord er and superfluidity. We report computational evidence of a supersolid phase of deuterium under high pressure ($p >800$ GPa) and low temperature (T $<$ 1.0 K). In our simulations, that are based on bosonic path integral molecular dynamics, we observe a highly concerted exchange of atoms while the system preserves its crystalline order. The exchange processes are favoured by the soft core interactions between deuterium atoms that form a densely packed metallic solid. At the zero temperature limit, Bose-Einstein condensation is observed as the permutation probability of $N$ deuterium atoms approaches $1/N$ with a finite superfluid fraction. Our study provides concrete evidence for the existence of a supersolid phase in high-pressure deuterium and could provide insights on the future investigation of supersolid phases in real materials.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا