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- Author or Editor: J. Lee x
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Abstract
Trace impurity elements in high purity copper metal (4 mine class) put on the market were analyzed by Instrumental Neutron Activation Analysis (INAA) and the results compared with those from Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS) and Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES). The sample irradiation was done at the irradiation facilities (thermal neutron flux, 5·1012 n·cm−2·s−1) of the TRIGA Mark-III research reactor in the Korea Atomic Energy Research Institute. Four unalloyed copper standards (NIST SRM # 393, 394, 395 and 398) were used to identify the accuracy and precision of the analytical procedure. The homogeneity of samples was assessed by means of the elements such as Ag, As, Co, Sb, Se and Zn. The analytical results of INAA, GFAAS and ICP-AES were in good agreement within expected uncertainties each other and showed the possibility of using them for the analytical quality control.
Abstract
In order to expand the utilization of phellinus mushrooms as a dietary supplement, we attempted to evaluate the chemical composition by measuring its inorganic elemental content with the aid of instrumental neutron activation analysis (INAA). Twenty seven phellinus mushrooms samples were collected from Korea, Cambodia, and Vietnam. A total of 28 elements were analyzed in the phellinus mushroom samples using the INAA. The concentrations of Ca, K, and Mg are much higher than those of other elements in phellinus mushroom samples. The sum of determined elemental concentration in Cambodia samples was about 2–6 times higher than those in Korea and Vietnam samples, respectively. Based on our measurement data, we attempted to discriminate the geographical origin using principal components analysis (PCA) and linear discriminant analysis (LDA). The geogrpahical origins of all samples were clearly classified with correct classification rate of 100%.
Abstract
In order to study the effects of air pollution, about 1,300 samples of airborne particulate matter (APM) were collected at suburban and industrial sites, in Daejeon, Korea from 1998 to 2006. The concentrations of carcinogenic (As and Cr) and non-carcinogenic metals (Al, Mn, and Zn) were determined by using instrumental neutron activation analysis (INAA). These long-term metal concentration data were applied to a risk assessment of inhalation exposure using Monte Carlo analysis (MCA).
Summary
Some stability and convergence theorems of the modified Ishikawa iterative sequences with errors for asymptotically nonexpansive mapping in the intermediate sense and asymptotically pseudo contractive and uniformly Lipschitzian mappings in Banach spaces are obtained.
Abstract
Evaluation of minimal detectable amounts (MDA) of iodine in various or specified irradiation and measurement conditions is described. Interfering contributions due to Na and Cl to the spectral background as well as the dead time of detection system were calculated in details based on an experimental approach. The MDA of iodine for some important biological samples with various Na and Cl concentrations can be evaluated and predicted according to the specified irradiation and measurement arrangements to meet the requirement of analytical purposes.
Abstract
Liquid scintillation spectrometry has become the most widespread method for quantitative analysis of low level 
-emitters in environmental samples. This technique has been applied in the measurements of 241Pu, 3H and 90Sr in seawater and sediment samples. 241Pu can be measured by direct analysis of an electrodeposited source using 
- discrimination or by extraction of electrodeposited plutonium into a liquid form compatible with scintillation cocktail. Sediment from Mururoa and Fangataufa atolls showed activities ranging from 18 to 44 Bq/kg. A sediment profile sampled around Bikini Atoll in 1997 showed 241Pu activities ranging from 0.3 to 30 Bq/kg. 3H activities in pore water sediment from Mururoa and Fangataufa atolls were of the order of 103 Bq/m3 which demonstrated its underground origin. 90Sr was measured in the presence of 90Y. The counting efficiency was 92.41.5% and the background 0.027±0.001 s-1. The average chemical recovery for 90Sr was 673%.
Field crops are subjected to numerous inconsiderate climatic hazards that negatively affect physiological processes, growth and yield. Drought is one of the major abiotic factors that limits the agricultural productivity especially in the arid and semi-arid areas of the globe. Silicon (Si) is a naturally occurring beneficial nutrient which modulates plant growth and development events and has been known to improve the crop tolerance to abiotic stresses. With the objective to investigate the role of silicon nutrition on maize hybrids under limited moisture supply, a two year field study was conducted during 2010–11 at Post Graduate Research Station (PARS), University of Agriculture Faisalabad, Pakistan. We evaluated growth of two maize hybrids P-33H25 and FH-810 under well watered (100% field capacity) and water deficit situation (60% field capacity) as affected by Si application. Silicon was added in soil @ 100 mg/kg using Calcium Silicate as source. Water deficit condition significantly reduced agro-morphological and physiological attributes of maize plants. Silicon application significantly increased the plant height, leaf area index, yield and related attributes along with improvement in photosynthetic rate, leaf water status and osmotic adjustment under limited moisture supply. It was concluded that silicon application to droughtstressed maize enhanced its growth and yield owing to improved photosynthetic rate, higher osmotic adjustment, increased water status and lowered transpiration.
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.
Abstract
The objective of this research was to design an extraction media and procedure that would selectively remove uranium without adversely affecting the soils' physicochemical characteristics or generating secondary waste forms difficult to manage or dispose of. Investigations centered around determining the best lixiviant and how the various factors such as pH, time, and temperature influenced extraction efficiency. Other factors investigated included the influence of attrition scrubbing, the effect of oxidants and reductants, and the recycling of lixiviants. Experimental data obtained at the bench-and pilot-scale levels indicated 80% to 95% of the uranium could be removed from the uranium-contaminated soils by using a carbonate lixiviant. The best treatment was three successive extractions with 0.25M carbonate-bicarbonate (in presence of KMnO4 as an oxidant) at 40°C followed with two water rinses.
Some examples are given of the application of thermogravimetry, differential scanning calorimetry, thermomechanical analysis, torsional braid analysis, stress relaxometry and dynamic viscoelastometry to the study of cross-linked polymer systems. The information derived by the use of each technique is outlined and the advantages and disadvantages of the different methods are compared.
