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Simulation Study for the Half-Life Measurement of 180mTa Using HPGe Detectors
G. W. Kim,S. Y. Park,I. S. Hahn,Y. D. Kim,M. H. Lee,D. S. Leonard,E. K. Lee,W. G. Kang,E. Sala,V. Kazalov 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.1
$^{180m}$Ta, which is the second excited state of $^{180}$Ta at E$_x$ = 77 keV, is naturally occurring and is the only known stable isomer. The half-life of $^{180m}$Ta is considered to be an important parameter for nuclear synthesis models for heavy elements. However, the decay of $^{180m}$Ta has never been observed even though several groups tried to measure it. We will search for gamma transitions from $^{180m}$Ta decays in a tantalum sample by using an array of fourteen HPGe detectors recently installed in an underground laboratory at Yangyang, Korea. In preparation for the measurement, Monte-Carlo simulation studies were conducted to optimize the tantalum sample configuration. Based on the simulation study, we decided on a configuration composed of a 2 mm thick disk with diameter of 200 mm and six 2 mm thick rectangular plates with dimension of 158 $\times$ 195 mm$^2$. The finalized tantalum sample configuration gives 2.0 and 7.5 coincidence events per year for the EC and the $\beta$-decay of $^{180m}$Ta, respectively. In this study, we used T$_{1/2}$ = 2.0~$\times$~10$^{17}$ years and T$_{1/2}$ = 5.8~$\times$~10$^{16}$ years for the EC and $\beta$-decay which are the present best lower-limits as reported by B. Lehnert \textit{et al.}
E. E. Pérez‑Ramírez,M. de la Luz‑Asunción,A. L. Martínez‑Hernández,G. de la Rosa‑Álvarez,S. Fernández‑Tavizón,P. Salas,C. Velasco‑Santos 한국탄소학회 2019 Carbon Letters Vol.29 No.2
One- and two-dimensional carbon nanomaterials were tested as adsorbents for the elimination of two anionic dyes, reactive red 2 and methyl orange, and the cationic dye methylene blue from aqueous solutions under the same conditions. Carbon nanomaterials performed well in the removal of dyes. Surface oxygenated groups in the nanomaterials improved the cationic dyes’ adsorption, but not the adsorption of the anionic dye. The interactions between nanomaterials and dyes were verified by infrared and Raman spectroscopy. The pseudo-second order kinetic model was better fitted to the kinetic experimental data than the Elovich and pseudo-first order models. The equilibrium adsorption data were best fitted by the Langmuir model. The dimensions and morphology of the carbon nanomaterials play an important role in the adsorption of the three dyes. The main mechanism of adsorption of anionic dyes is by the interactions of the aromatic rings of the dye structures and π delocalized electrons on carbon nanostructures; the adsorption of cationic dye is mainly due to electrostatic interactions.
Salas, R.C.D.,van der Lende, T.,Udo, H.M.J.,Mamuad, F.V.,Garillo, E.P.,Cruz, L.C. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.5
Data collected between 1981 and 1991 at the Philippine Carabao Center at Central Luzon State University (PCC-CLSU) were used for the comparison of growth, milk yield and draughtability of Murrah-Philippine crossbred and Philippine native buffaloes. Body weights and body measurements were available at 3-month intervals from birth to 36 months of age for a total of 34 $Murrah{\times}Philippine$ native buffalo F1 crossbreds (CBB; 21 cows, 13 bulls) and 32 Philippine native buffaloes (PNB; 16 cows, 16 bulls). Lactation records were available for 14 CBB and 19 PNB cows. Data for draughtability under wet and dry ploughing conditions were available for 4 CBB and 4 PNB steers. The results indicate that crossbreds grow faster (0-9 months of age: cows $442{\pm}19$ vs. $301{\pm}21g/day$, bulls $305{\pm}23$ vs. $296{\pm}21g/day$; 9-36 months of age: cows $227{\pm}10$ vs. $147{\pm}12g/day$, bulls $282{\pm}13$ vs. $138{\pm}12g/day$), mature earlier and produce more milk (1st lactation: $1139{\pm}153$ vs. $450{\pm}112kg$; 2nd lactation: $1115{\pm}132$ vs. $488{\pm}136kg$) than native buffaloes, but have a poorer draughtability (wet ploughing; force as % of body weight $8.8{\pm}0.2$ vs. $12.2{\pm}0.6$; dry ploughing: cut depth $10.98{\pm}0.25$ vs. $11.92{\pm}0.13cm$, velocity $0.50{\pm}0.03$ vs. $0.60{\pm}0.02m/sec$, force as % of body weight $9.0{\pm}0.6$ vs. $11.3{\pm}0.7$). The correlation coefficients between body weight and body measurements at birth and at 3-month intervals indicate that heart girth has a relatively high correlation with body weight, especially in crossbreds. It is concluded that in Philippine smallholder farming systems in which meat and milk production are secondary to draught power, the native buffalo is preferable from the point of view of input needed to maintain the number of animals kept for a required draught force.