• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.153-158
• /
• 2000

Nuclear reactor pressure vessel should be safety even in the case that hypothetical defects with allowable size are in vessel. Therefore, the materials should have excellent fracture resistance characteristics. The purpose of this study is to analyze the results of preirradiation baseline test of nuclear pressure vessel for Yonggwang Unit 5/6. In experiments, drop weight tests and impact tests are carried out to obtain nil-ductility transition reference temperature, $RT_{NDT}$ and static and dynamic fracture toughness tests are performed to compare with $K_{IR}$ curve in accordance with ASME Sec.III. The test results show that the materials had sufficiently fracture resistance characteristics for 40 years of design life.

• Polymer(Korea)
• /
• v.30 no.4
• /
• pp.305-310
• /
• 2006

The hybrid cation exchange fibers using graft copolymer of styrene onto PE/PP with PET trunk polymers were synthesized by electron beam preirradiation. The degree of grafting showed 123% value at 80% concentration of styrene. And also, amount of sulfonyl group in the ion exchanger was showed 3.3 mmol/g at 70% concentration of styrene and their values were constant after 70%. The tensile strength for fibers was lower than trunk fibers, and their value of ion exchange fibers were also below than copolymer. It was $0.206kgf/mm^2$ value. The breakthrough time for Ca and Mg ions of hybrid cation exchange fibers were increased with the increase in the pH and temperature. The breakthrough of Mg was slower the mixture than single Mg solution. Adsorption rate constant for Ca, Mg ions and maximum ion exchange capacity were 0.012, 0.011 L/mg.h and 47.06, 42.83 mg/g, and also, activation energies were 2169 and 1534 J/mol, respectively.

• Applied Chemistry for Engineering
• /
• v.10 no.3
• /
• pp.477-485
• /
• 1999

The grafting of 2,3-epoxypropylmethacrylate (GMA) onto polypropylene fabric was carried out by the $\gamma$-ray preirradiation grafting technique. Subsequently, the GMA-grafted polypropylene fabric was reacted with iminodiacetic acid (IDA) in different mixed solvents to prepare the fibrous metal adsorbent. The grafting extent was found to be dependent on the reaction time, temperature, preirradiation dose and dose rate. The effects of various mixed solvents on the IDA amination onto GMA-grafted polypropylene fabric were investigated. Compared with other mixed solvents, the extent of amination was highest in the dimethylsulfoxide (DMSO)/water, but the reaction did not occur in the water. The adsorption characteristics of various metal ions by the prepared adsorbent were examined when it was immersed in the 100 ppm metal ion solution. The amount of adsorption followed the order:$Pb^{2+}>Co^{2+}>Fe^{2+}$.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.04a
• /
• pp.99-101
• /
• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• Textile Coloration and Finishing
• /
• v.15 no.2
• /
• pp.102-108
• /
• 2003

Before studying graft polymerization of PP(polypropylene) nonwoven fabrics by electron beam preirradiation method, mechanical properties, thermal properties and degree of crystallinity of original and electron beam irradiated PP nonwoven fabrics were investigated. Morphological surface changes of electron beam irradiated PP nonwoven fabrics were not observed. And the melting temperature and crystallinity of electron beam irradiated PP nonwoven fabrics also did not change as compared with untreated PP nonwoven fabrics. But the breaking strength of electron beam irradiated PP nonwoven fabrics decreased with increasing electron beam absorbed dose due to breakdown of some parts of polymer main chain.

• Textile Coloration and Finishing
• /
• v.15 no.3
• /
• pp.154-160
• /
• 2003

Polypropylene nonwoven fabrics were grafted with acrylic acid by a preirradiation method by using electron beam accelerator. The effect of irradiation dose, storage time, concentration of acrylic acid, reaction temperature, reaction time and Mohr's salt concentration on the degree of grafting were investigated in detail. The grafted Polypropylene nonwoven fabrics were characterized using IR spectroscopy and SEM. The results showed that the degree of grafting increased with increasing absorbed dose and the Mohr's salt in the acrylic acid solution promoted grafting efficiency.

• Nuclear Engineering and Technology
• /
• v.50 no.8
• /
• pp.1421-1425
• /
• 2018

The dynamics of gas release at thermal oxidation of extraction systems on the basis of diamides of dicarbonic acids in fluorinated sulphones with 14 mol/L $HNO_3$ was investigated. The effect of preirradiation of the mixtures with accelerated electrons on the kinetics of their thermolysis was determined. The mixtures were heated in an autoclave at temperatures of 170 and $200^{\circ}C$ and irradiated using an electron accelerator to absorbed doses of 0.1, 0.5, and 1.0 MGy. It has been shown that no conditions for autocatalytic oxidation at thermolysis of extraction mixtures irradiated up to a dose of 1 MGy were developed.

• Journal of Food Hygiene and Safety
• /
• v.13 no.3
• /
• pp.232-237
• /
• 1998

The purpose of this study is to examine the phototoxicity of four phenothiazine derivatives such as chlorpromazine, perphenazine, trifluoroperazine and promethazine, and to investigate the effects of ascorbic acid on their phototoxicity by UVB irradiation. Effects of the test compounds on RBCs were monitored with a spectrophotometer by the method of Kahn et al. The extent of photohemolysis by tested phenothiazine derivatives were increased with their concentration and toxic photoproducts were formed by chlorpromazine and promethazine with preirradiated UVB. Photohemolysis postirradiated chlorpromazine and perphenazine and preirradiated promethazine were decreased with the use of ascorbic acid significantly.

• Advances in materials Research
• /
• v.3 no.4
• /
• pp.183-197
• /
• 2014

Copolymers of gelatin and poly (vinyl alcohol), (PVA) grafted by acrylic acid (AAc) with excellent water absorption and retention abilities under neutral conditions were successfully synthesized using $^{60}Co$ gamma radiations in presence of ammonium persulphate (APS), as water soluble initiator and sodium bicarbonate ($NaHCO_3$) as foaming agent. The optimum synthesis conditions pertaining to maximum swelling percentage were evaluated as a function of gelatin/PVA ratio, amount of water, concentration of APS, $NaHCO_3$, monomer concentration and total irradiation dose. Maximum percent swelling (1694.59%) of the copolymer, gelatin-co-PVA, was obtained at optimum $[APS]=2.92{\times}10^{-1}mol/L$, $[NaHCO_3]=7.94{\times}10^{-2}mol/L$ and 1.5 mL of water at total dose of 31.104 kGy while in case of grafted copolymer, (gelatin-co-PVA)-g-poly(AAc), maximum percent swelling (560.86%) was obtained using $8.014{\times}10^{-1}mol/L$ of AAc in 9 mL water with 31.104 kGy preirradiation dose. The pristine and grafted copolymers were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron Microscopy (SEM), Thermal gravimetric analysis (TGA) and X-Ray Diffraction (XRD) methods. The copolymers loaded with an antiseptic, Povidone, were used as wound dressing materials for wounded gastrocnemius muscle of mice and the results exhibit that (gelatin-co-PVA)-g-poly (AAc) copolymer is a potent wound dressing material as compared to the copolymer.

• The Korean Journal of Zoology
• /
• v.14 no.3
• /
• pp.119-124
• /
• 1971

Male mice of strain SM were given 128 rads of single whole-body gamma-irradiation of $^{60}Co$, 14 to 16 minutes following a subcutaneous injection of physiological saline or cortisone acetate (1mg/day, for 4 days preirradiation). The serum protein patterns and the level of the total serum proteins were determined at various time intervals after exposure. Total serum protein was determined by Biuret method and serum protein fractions and A/G ratio were determined by paper electrophoresis using Whatman No.1 filter paper and barbital buffer (pH 8.6, ionic strength 0.06). 1. Total body gamma-irradiation caused a rise in the level of the total serum protein at 1 day and in the level of the serum albumin-globulin ratio at 5 days in both cortisone acetate-treated and control groups. 2. Cortisone acetate delayed the total serum protein rise at 5, 10, and 20 days after exposure. 3. Cortisone acetate delayed the A/G ratio rise at 1, 5, and 10 days after exposure. 4. It may be inferred that cortisone greatly reduces the sensitivity of mice to gamma-irradiation on the blood protein, probided that cortisone is given before the exposure.