Authors:Long Han, Deepak Doraiswamy, and Rakesh K. Gupta
Light emitting devices containing conjugated polymers are conveniently fabricated using ink-jet printing. A common problem in the processing of these materials is that the Newtonian viscosity of the polymer solution is not sufficient to describe the jetting performance because the molecular weights and concentrations employed are such that the resulting solutions are elastic. These differences in fluid elasticity levels cannot be measured using traditional techniques like dynamic mechanical experiments or the first normal stress difference in shear, but strongly impact the jetting behavior of the liquid. In this study, a variety of polystyrene solutions in DECALIN having a shear viscosity of ~5 mPa s but different elasticity levels were examined for their jetting behavior. The jetting behavior of these solutions was studied visually using drop-on-demand jetting equipment and their rheology was characterized using a custom extensional rheometer designed for measuring the elasticity of such low viscosity liquids. If elasticity effects are absent as in Newtonian liquids (corresponding to a Trouton ratio of 3) satellite drops are formed resulting in loss of liquid and poor positioning. On the other hand, if elasticity effects are very large (Trouton ratios ≫4) separation problems occur at the nozzle with undesirable “tailing.” The optimum range for stable, efficient jetting occurs at Trouton ratios in a narrow band between 3 and ~5. A very slight degree of elasticity corresponding to a Trouton Ratio around four thus seems to be optimum for the jetting process. This appears to be the first time that such a design criterion has been outlined for this process. Such an approach complements thermal techniques for elucidating the role of molecular and flow properties on the processing behavior of polymeric systems.
Authors:X. Liu, H. Zhang, Z. Tan, K. Han, and L. Sun
The isoquinoline alkaloids were isolated from traditional Chinese drugs of Phellodendri Cortex, Radix Stephaniae Tetrandrae,
Corydalis Yanhusuo and Corydalis Bungeana. The power-time curves of growth of E. coli at different concentrations of isoquinoline alkaloid at 37�C were determined by a 2277 Thermal Activity Monitor. The rate
constant of bacteriostastic activity was calculated. The relationship between growth rate constant and concentration was established.
The optimum bacteriostastic concentration was determined. Experimental results have indicated that all the isoquinoline alkaloids
isolated from the four kinds of traditional Chinese drugs have bacteriostastic activity and the order is Phellodendri Cortex>Radix
Stephaniae Tetrandrae>Corydalis Yanhusuo>Corydalis Bungeana.
Temperature programmed combustions (TPC) of Yang-Quan anthracite, Liao-Cheng lean coal and Li-Yan bituminous coal in oxy-fuel
atmosphere were conducted in a thermogravimetric analyzer and characteristic parameters were deduced from the TG-DTG curves.
The results showed that combustion got harder to progress as the coalification degree increasing. Within range of 40%, effect
of heightening O2 concentration favored the combustion process, but beyond this zone, the effect leveled off. The model-fitting mathematical
approach was used to evaluated the kinetic triplet (f (α), E, A) through Coats–Redfern method. The calculation showed that D3-Jander was the proper reaction model and the evaluations of E and A validated the experimental results.
It is regarded that the spent resins from the water purification systems of moderator (MOD) and the primary coolant of the
Canada deuterium uranium-pressurized heavy water reactor (CANDU-PHWR) are a unique waste, owing to their high 14C and gamma-emitting nuclides. In this work, 14C and 3H contents, anion and cation fractions and the predominant gamma-emitting nuclides of the spent resins from 4 units of CANDUPHWRs,
were investigated. Also the chemical species of 14C of the spent resins were determined. For a simultaneous separation of 14C and 3H from the spent resins, the wet oxidation-16 wt% H2SO4 stripping process was utilized. The 14C and 3H activity concentration range of the spent resins of the nuclear power plant (NPP), 4 units of all CANDU-PHWR types, was
2.48E5 Bq/g ∼5.33E6 Bq/g, 1.29E5 Bq/g and ∼2.33E5 Bq/g, respectively. Among the analyzed spent resins, the highest 14C and 3H activity concentration was detected in units 4 and 3, respectively. It was found that more than 92% of the 14C activity concentration was retained on the anion resin and the predominant chemical species was inorganic 14C. It was revealed that the anion resin fraction of the spent resins from unit 1 and unit 2, was about 40% and that of unit
3 and unit 4 was around 60%. More than 80% of the total gamma-radioactivity concentration was associated with the cation fraction
of the spent resin. The predominant gamma-emitting nuclide of the spent resin for unit 2 was 137Cs, a fission product, and that for unit 4 was 60Co, a corrosion product.
Authors:U. Park, J. Lee, K. Son, H. Han, and S. Nam
In order to develop an 125I seed for brachytherapy of prostate cancer, a carrier body consisting of Al2O3 and silver powder was developed. To optimize the adsorption conditions of 125I on the rods, various experiments were performed. The adsorption capacity was more than 95% after 4 hours at a volume of
50 μl containing about 5 mCi of 125I. Dosimetric properties were measured for the radial and longitudinal directions. Variations were below 11% in the longitudinal
distribution and 5% in the radial distribution. This method is effective for the preparation of 125I seeds to be used in brachytherapy treatment.
Authors:H. Han, W. Cho, U. Park, Y. Hong, and K. Park
The Korea Atomic Energy Research Institute (KAERI) completed the High-flux Advanced Neutron Application Reactor (HANARO) in 1995 and the radioisotope production facilities(RIPF) in 1997. Many devices and handling tools were developed and applied for the production of radioisotopes. Emphasis on RI production plan was placed on the development of new radiopharmaceuticals, the development of new radiation sources for industrial use and the steady production of selected radioisotopes. The selected items are 166Ho-based pharmaceuticals, fission 99Mo/99mTc generators, and products of 131I and 192Ir and 60Co sources for industrial use. Now KAERI regularly produces radioisotopes (131I, 99mTc, 166Ho, 192Ir, 60Co etc.) and labeled compounds including 99mTc cold kits. Newly developed therapeutic agents are a 166Ho-chitosan complex for liver cancer treatment, a 166Ho patch for skin cancer treatment and devices such as the stent and balloon for the prevention against restenosis of the coronary artery. Feasibility studies on the installation of a 99mTc generator loading facility and on 60Co production for food irradiation were finished. The 192Ir sealed source assembly for NDT has been supplied to domestic users since May 2001. The fission moly process, separation process of non-sealed sources (125I, 33P, 89Sr, 153Sm, 188Re) and fabrication process of sealed sources (169Yb, 75Se) are also under development. For the quality assurance of our final products, we obtained ISO certification in 2000. We are carrying out a feasibility study on a new research reactor for the stable supply of radioisotopes in Korea.
Authors:J. Lee, J. Kim, K. Cho, J. Woo, M. Han, and Y. Chung
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.
Polysaccharides from litchi (Litchi chinensis) seeds were isolated and puriﬁed using ion exchange column chromatography. Molecular weight distribution of polysaccharides and monosaccharides were detected. Preliminary structural characterisation of polysaccharides was conducted using infrared, nuclear magnetic, and other spectroscopy techniques in combination with methylation analysis. In vitro cell culture experiments were designed to detect the eﬀects of polysaccharides on cell growth and cellular glucose consumption. We extracted and analysed three polysaccharides from litchi seed. Monosaccharide composition and infrared spectroscopy detection showed that the skeleton structure of polysaccharides consisted of glucose and mannose. Polysaccharides 1 and 2 are similar and have relatively high glucose content (around 70%); polysaccharide 3 has 39.17% glucose only but is rich in arabinose (about 21.03%). In a certain range of use (50~1000 μg ml–1), polysaccharides 1 and 2 have no signiﬁcant impacts on cell growth, while polysaccharide 3 can promote proliferation to some extent. All three polysaccharides can promote in vitro cellular glucose consumption, especially polysaccharide 3, which shows the strongest promotion, a signiﬁcant dose eﬀect, and synergistic eﬀect with insulin. The above results highlight important roles of litchi seed polysaccharides in promoting cell growth and validate litchi seed polysaccharides as potential drugs for hypoglycaemia.
Authors:M. Tsukada, D. Sato, K. Endo, M. Yanaga, L. Currie, M. Glascock, J. Ondov, and M. Han
Instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectroscopy (ICP-MS) were applied to the determination of major elements and rare earth elements in Japanese Standard Soil Materials (NDG-1 to -8). Eight major elements, Al, Fe, Ti, Ca, Mg, Mn, K, and Na were determined by INAA. A comparison of the data for rare earth elements obtained by INAA and ICP-MS shows that the data of the contents determined by the two different analytical methods are in fairly good agreement with each other.
Authors:S. D. Park, H. N. Lee, H. J. Ahn, J. S. Kim, S. H. Han, and K. Y. Jee
It is impossible to detect 14C and 3H by direct methods such as γ-spectroscopy because they are pure b-emitters and thus they are classified as hard to measure
nuclides (HTM). In this paper the analysis results of 14C and 3H in the low level radioactive wastes (LLWs), including spent ion exchange resin, evaporated bottom and sludge are presented.
The LLWs were generated by three nuclear power plants (NPPs), in Korea all with pressurized water type reactors (PWRs). A
simultaneous separation procedure for 14C and 3H in LLWs was established by wet oxidation-acid stripping. A liquid scintillation analyzer was used for the measurement of
14C and 3H. It was found that the recovery of 14C and 3H was 82-99 and 78-103%, respectively, by wet oxidation-acid stripping with diluted standard solutions. At the lowest injection
of 14C and 3H, i.e., at 1.44 Bq for 14C and 1.22 Bq for 3H, the minimum detectable activity (MDA) of 14C and 3H was calculated as 0.88 and 0.78 Bq/g, respectively, for the minimum allowable sample weight, using wet oxidation and 16
wt% H2SO4 acid. By the wet oxidation-16 wt% H2SO4 stripping method no interfering nuclides were detected in the trapping solution of 14CO2 and the distillate of 3H. The activity concentration range of 14C in the analyzed samples, i.e., spent ion exchange resin, evaporated bottom and sludge, was 0.17-110,000, 8.4-1380 and 0.1-10,006
Bq/g, respectively, and that of 3H in the same was from no detectable to 769, 134-14,383 and 0.7-4820 Bq/g, respectively.