The influence of co-ions in the eluent on the separation factor () of lithium isotope separation has been studied by ion exchange chromatography. A strongly acid cation exchange resin (Dowex 50W-X8) was used for the separation of lithium isotopes. The co-ions used in eluent were H+, K+, Ba2+, Cu2+, Al3+ and Cr3+ as their chlorides. From the experiments, it was found that6Li was enriched in the resin phase and7Li in solution phase. At the same distribution coefficient (Kd=30), the separation factor increased linearly with the charge of co-ion (=1.0022 to 1.0039).
On utilise trois radioisotopes facilement détectés38Cl,34mCl et38K, produits à partir du soufre, du chlore, de la potasse et du calcium pour doser ces éléments par activation au3He. On a analysé un certain nombre d'échantillons de façon non-destructive en utilisant différentes réactions nucléaires pour
examiner la précision de la méthode et l'étendue des interférences. On donne les fonctions d'excitation absolue pour les réactions
nucléaires aux hélions 3.
Radiation treatment in the presence of catalysts such as anatase, P25 and bentonite showed efficient removal of TCE (trichloroethylene) and PCE (perchloroethylene) compared with gamma-irradiation alone. Gamma-ray pretreatment of P25 and bentonite enhanced the decomposition of TCE and PCE, respectively. The change in the catalysts by gamma-rays was characterized by their EPR spectra. For anatase and bentonite, the peaks in the spectra increased significantly, and the pattern of the spectra changed in the case of P25. The relationship between the peaks and pollutant decomposition should be further clarified due to the complexity of the spectra.
Authors:J. M. Greenwood-Lee, P. D. Taylor, and D. Haig
We develop a general inclusive fitness model for genetic evolution at an imprinted locus – one at which selection is allowed to act conditionally upon parental origin of the gene. In many cases of interest, such genes affect the fitness of relatives, particularly sibs. We formulate a matrilineal and patrilineal inclusive fitness and show that these can be used to describe the dynamics of change in mean expression levels. We classify and analyze the stability of equilibrium points and apply our results to some examples that have appeared in the literature, multiple paternity of a female's offspring, the “ovarian time-bomb,” and loss-of-function mutations.
Authors:D. Kim, B. Kim, S. Park, N. Lee, Y. Jeon, K. Choi, and Y. Lee
A study on the separation of lithium isotope was carried out with N4O azacrown ion exchange resin. The lighter6Li isotope concentrated in the solution phase, while the heavier7Li isotope is enriched in the resin phase. Upon column chromatography (0.3 cm I.D.×15.5cm height) using 0.5M NH4Cl as an eluent, single separation factor, α=1.00127 was obtained.
Authors:D. Kim, C. Kim, J. Jeon, J. Kim, and N. Lee
The novel N4S2 azacrown ion exchange resin was prepared. The ion exchange capacity of N4S2 ion exchanger was 0.34 meq/g dry resin. A study on the separation of lithium isotopes was carried out with N4S2 azacrown ion exchange resin. The lighter isotope,6Li is concentrated in the resin phase, while the heavier isotope,7Li is enriched in the solution phase. With column chromatography [0.1 cm (I.D.)×32 cm (height)] using 2.0M NH4Cl as an eluent, separation factor, a=1.034 was obtained.
Authors:D. Kim, J. Kim, J. Jeon, H. Kim, and N. Lee
The novel NDOE (1,12,15-triaza-3,4:9,10-dibenzo-5,8-dioxacycloheptadecane) ion exchange resin was prepared. The ion exchange
capacity of NDOE azacrown ion exchanger was 0.2 meq/g dry resin. A study on the separation of lithium isotopes was carried
out with NDOE novel azacrown ion exchange resin. The lighter isotope,6Li concentrated in the solution phase, while the heavier isotope,7Li is enriched in the resin phase. By column chromatography (0.1 cm I.D.×32 cm height) using 2.0M NH4Cl as an eluent, a separation factor,a=1.0201 was obtained.
Authors:D. Kim, Y. Jeon, T. Eom, M. Suh, and C. Lee
A study on the separation of Li isotopes was carried out with a resin having monobenzo-15-crown-5 as a functional group, synthesized by substitution reaction of chloromethylated styrene-DVB copolymer with 4-aminobenzo-15-crown-5. Adsorption properties of the resin for Li+ were invesgated with batch method in various solvents and counter anions. Upon column chromatography [0.9 cm (I. D.)×25 cm (height)] using 5% (v/v) H2O in acetonitrile as an eluent, single separation factor, , 1.053 (±0.005), (6Li/7Li)resin/ (6Li/7Li) solution was obtained by the GLUECKAUF method from the elution curve and isotope ratios.
Authors:H. Yang, E. Lee, J. Lim, D. Chung, and K. Kim
The extraction of Am(III) and Eu(III) using a γ-pre-irradiated N,N′-dimethyl-N,N′-dibutyltetradecyl malonamide (DMDBTDMA)
modified with N,N′-dihexyloctanamide (DHOA) in n-dodecane (NDD) at 4.5M HNO3 has been studied as a function of the absorbed dose up to 2×106 Gray. The distribution ratios of Am(III) and Eu(III) were almost constant until a dose of 1×105 Gray and then they decreased gradually up to a dose of 2×106 Gray. The decrease of the distribution ratios of Am(III) and Eu(III) are due to the decreasing concentration of the DMDBTDMA
by a γ-pre-irradiation and these results were supported by a determination of the DMDBTDMA concentration with a gas chromatography
method. The distribution ratios of Am(III), Eu(III), Ce, Nd and Y with γ-pre-irradiated (DMDBTDMA-DHOA)/NDD have also been
studied as a function of the nitric acid concentration and the extraction temperature.
Authors:J. Brockman, D. Nigg, M. Hawthorne, M. Lee, and C. McKibben
A new research effort aimed at increasing the catalog of boron delivery agents for boron neutron capture therapy (BNCT) has
been undertaken by the International Institute of Nano and Molecular Medicine (IINMM) at the University of Missouri. The MU
Research Reactor (MURR) and Idaho National Laboratory (INL) have constructed a facility for small animal BNCT experiments.
The facility incorporates silicon and bismuth single crystal filters to produce a thermal neutron beam. The thermal beam has
a measured thermal flux of 8.8 × 108 n cm−2 s−1 and a gold cadmium ratio of 130. The neutron and photon dose rates were measured using paired ion chambers.