• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.541-546
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• 2003

Experimental vapor pressure measurements available in the literature for the inert gases have been rigorously analyzed and used to evaluate the constants A, B, C, D, and exponent of the following equation in the form of reduced vapor pressure and reduced temperature : $InP_r=A+{\frac{B}{T_r}+CInT_r+DT_n^r}$ According to varying exponent n all four constants have been obtained for the inert gases by the error analysis. This has provided us the best n and four constants for each of the inert gases ; Argon, krypton, xenon, helium, and neon. In order to obtain the calculated vapor pressure by the above equation, only the normal boiling point and the critical pressure and critical temperature are necessary to get the vapor pressure for an overall average deviation of 0.31 % for 406 experimental vapor pressure points consisting of five gases available in the literature. The average deviation for argon, krypton, and xenon is 0.24%, 0.09%, and 0.22%, respectively, for neon 1.31% and for helium 0.61%. These results are not unexpected in view of the significant quantum effects associated with helium and to a lesser degree with neon.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.104-108
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• 2008

Accurate sets of electron collision cross sections and the electron transport coefficients for atoms and molecules are necessary for quantitative understanding of plasma phenomena Kr and Xe atom are used in many industrial applications, such as in PDP and fluorescent induction lamps(FILs). Therefore, we analysed and calculated the electron transport coefficients, the electron drift velocity W, the longitudinal and transverse diffusion coefficient $ND_L$ and $ND_T$, and the ionization coefficient $\alpha$/N in pure Kr and Xe gases over the wide E/N range from 0.001 to 500[Td] at 1[Torr] by two-tenn approximation of the Boltzmann equation.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.211-217
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• 1982

Assuming krypton molecules adsorbed on the graphite surface as a two-dimensional (2D) gas, 4th virial coefficient of the virial equation is calculated by the use of cluster integrals. The Henry's law constant, and 2nd and 3rd virial coefficients are also calculated. Adsorption isotherms calculated from this virial equation agree very satisfactorily with experimental results. The interaction energy of Kr-graphite surface is calculated assuming the pairwise additivity of Lennard-Jones(12,6) potential, and parametars therein are taken as; ${\varepsilon}_{gs}$/k = 71.1 K, ${\varepsilon}_{gg}$/k = 170 K, ${\sigma}_{gs}$ = 354 pm, and ${\sigma}_{gg}$ = 368 pm.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.1023-1029
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• 2001

The positions of Kr atoms encapsulated in the molecular-dimensioned cavities of fully dehydrated zeolite A of unit-cell composition Cs3Na8HSi12Al12O48 (Cs3-A) have been determined. Cs3-A was exposed to 1025 atm of krypton gas at 400 $^{\circ}C$ for four days, followed by cooling at pressure to encapsulate Kr atoms. The resulting crystal structure of Cs3-A(6Kr) (a = $12.247(2)\AA$, R1 = 0.078, and R2 = 0.085) has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at $21(1)^{\circ}C$ and 1 atm. In the crystal structure of Cs3-A(6Kr), six Kr atoms per unit cell are distributed over three crystallographically distinct positions: each unit cell contains one Kr atom at Kr(1) on a threefold axis in the sodalite unit, three at Kr(2) opposite four-rings in the large cavity, and two at Kr(3) on threefold axes in the large cavity. Relatively strong interactions of Kr atoms at Kr(1) and Kr(3) with Na+ ions of six-rings are observed: Na-Kr(1) = 3.6(1) $\AA$ and Na-Kr(3) = $3.08(5)\AA.$ In each sodalite unit, one Kr atom at Kr(1) was displaced $0.74\AA$ from the center of the sodalite unit toward a Na+ ion, where it can be polarized by the electrostatic field of the zeolite, avoiding the center of the sodalite unit which by symmetry has no electrostatic field. In each large cavity, five Kr atoms were found, forming a trigonal-bipyramid arrangement with three Kr(2) atoms at equatorial positions and two Kr(3) atoms at axial positions. With various reasonable distances and angles, the existence of Kr5 cluster was proposed (Kr(2)-Kr(3) = $4.78(6)\AA$ and Kr(2)-Kr(2) = $5.94(7)\AA$, Kr(2)-Kr(3)-Kr(2) = 76.9(3), Kr(3)-Kr(2)-Kr(3) = 88(1), and Kr(2)-Kr(2)-Kr(2) = $60^{\circ}).$ These arrangements of the encapsulated Kr atoms in the large cavity are stabilized by alternating dipoles induced on Kr(2) by four-ring oxygens and Kr(3) by six-ring Na+ ions, respectively.

• Journal of the Optical Society of Korea
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• v.2 no.2
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• pp.50-53
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• 1998

We report on the spectroscopic investigation of optical-field ionized plasmas in the soft X-ray spectral region. The experiment was carried out by focusing pulses of the high-power Ti:Sapphire laser with an energy of ~ 40 mJ and time duration of ~30 fs into a gas jet of krypton, xenon, and argon from a pulsed nozzle. Strong soft X-ray emission on lines from ionic stages of $Kr^{7+} , Kr^{8+} , Xe^{7+} , Ar^{7+} , and Ar^{8+}$ is reported. The experimental result was found to be in good agreement with theoretical prediction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.29-35
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• 2012

Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under high gravity acceleration of $10g_0$ appear considerably larger than those under normal gravity acceleration ($1g_0$). With increasing the gravity acceleration from $1g_0$ up to $10g_0$, the total molar flux for ${\Delta}T$ = 30 K increases by a factor of 4, while for ${\Delta}T$ = 90, by a factor of 3. The maximum molar fluxes for three different gravity levels of $1g_0$, $4g_0$ and $10g_0$, appear approximately in the neighborhood of y = 0.5 cm, and the molar fluxes show asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. As the gravitational level is enhanced form $1g_0$ up to $10g_0$, the intensity of convection is increased significantly through the maximum molar fluxes for ${\Delta}T$ = 30 K and 90 K. At $10g_0$, the maximum total molar flux is nearly invariant for for ${\Delta}T$ = 30 K and 90 K. The total molar flux increases with increasing the gravity acceleration, for $1g_0{\leq}g_y{\leq}10g_0$, and decreases with increasing the partial pressure of component B, a noble gas called as Kr (Krypton), $P_B$. The ${{\mid}U{\mid}}_{max}$ is directly proportional to the gravity acceleration for 20 Torr $P_B{\leq}300$ Torr. As the partial pressure of $P_B$ (Torr) decreases from 300 Torr to 20 Torr, the slopes of the ${{\mid}U{\mid}}_{max}s$ versus the gravity accelerations increase from 0.29 sec to 0.54 sec, i.e. by a factor of 2. The total molar flux of $Hg_2Cl_2$ is first order exponentially decayed with increasing the partial pressure of component B, $P_B$ (Torr) from 20 Torr up to 300 Torr.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.246-252
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• 1981

Assuming krypton molecules adsorbed on graphite surface as 2D gas, the interaction energy of Kr-graphite and the Henry's constant are calculated analytically by the Fourier series expansion method. 2D virial cofficients, $B_{2D}$ and $C_{2D}$, are also calculated to obtain 2D equation of state, and hence adsorption isotherms. The isotherms so obtained are compared with experimental results reported by Putnam and Fort. The pairwise additivity of Lennard-Jones(12, 6) interaction energy is also assumed, and parameters therein are taken as; ${\varepsilon}_{gs}$/k = 70 K, ${\sigma}_{gs}$ = 0.35 nm, ${\varepsilon}_{gg}$/k = 170 K, and ${\sigma}_{gg}$ = 0.37 nm.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.144-157
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• 2022

Noble gases, which are chemically inert and behave conservatively in marine environments, have been used as tracers of physical processes such as air-sea gas exchange, mixing of water masses, and distribution of glacial meltwater in the ocean. For precise measurements of Ne, Ar, and Kr, we developed a mass spectrometric system consisting of a quadrupole mass spectrometer (QMS), a high vacuum preparation line, an activated charcoal cryogenic trap (ACC), and a set of isotope standard gases. The high vacuum line consists of three sections: (1) a sample extraction section that extracts the dissolved gases in the sample and mixes them with the standard gases, (2) a gas preparation section that removes reactive gases using getters and separates the noble gases according to their evaporation points with the ACC, and (3) a gas analysis section that measures concentrations of each noble gas. The ACC attached to the gas preparation section markedly lowered the partial pressures of Ar and CO₂ in the QMS, which resulted in a reduced uncertainty of Ne isotope analysis. The isotope standard gases were prepared by mixing ²²Ne, ³⁶Ar, and ⁸⁶Kr. The amounts of each element in the mixed standard gases were determined by the reverse isotope dilution method with repeated measurements of the atmosphere. The analytical system achieved precisions for Ne, Ar, and Kr concentrations of 0.7%, 0.7%, and 0.4%, respectively. The accuracies confirmed by the analyses of air-equilibrated water were 0.5%, 1.0%, and 1.7% for Ne, Ar, and Kr, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2310-2316
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• 2016

We studied the effect of $Co^{60}$ gamma-radiation on the fiber Bragg gratings (FBGs) by irradiation time of UV Krypton fluoride (KrF) excimer laser among grating processing parameters. The FBGs were fabricated in a different UV laser irradiation time at 30, 60, 90, and 120 seconds using the same commercial Ge-doped silica core fiber (SMF-28e). It was exposed to gamma-radiation up to a high dose of 34.3 kGy at the dose rate of 106 Gy/min, and then it was analyzed radiation effects by measuring the radiation-induced change in the temperature sensitivity coefficient and Bragg wavelength shift. According to the experimental results, We confirmed that the UV laser irradiation period for grating inscription has a highly effect on the radiation sensitivity of the FBGs. The radiation-induced Bragg wavelength shift by the change of laser irradiation conditions showed a difference more than about 50 %.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.301-308
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• 2018

Anthropogenic radioactive noble gases formed by nuclear fission are significant indicators used to monitor the nuclear activity of neighboring countries. In particular, radioactive xenon, owing to its abundant generation and short half-life, can be used to detect nuclear testing, and radioactive krypton has been used as a tracer to monitor the reprocessing of nuclear fuels. Released radioactive noble gases are in the atmosphere at infinitesimal amounts due to their dilution in the air and their short half-life decay. Therefore, to obtain reliable and significant data when performing measurement of noble gases in the atmosphere, the minimum detectable activity (MDA) for noble gases should be defined as low as possible. In this study, the MDA values for radioactive xenon and krypton were theoretically obtained based on the BfS-IAR system by collecting both noble gases simultaneously. In addition, various MDA methods, confidence level and analysis conditions were suggested to reduce and optimize MDA with an assessment of the factors affecting MDA. The current investigation indicated that maximizing the pretreatment efficiency and performance maintenance of the counter were the most important aspects for Xe. In the case of Kr, since sample activities are much higher than those of Xe, it is possible to change the target MDA or to simplification of the analysis system.