• Proceedings of the Safety Management and Science Conference
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• 2002.11a
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• pp.253-259
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• 2002

The value of charge currnet, discharge current, ${\varepsilon}r^'$,${\varepsilon}r^{'}$ residual voltage was measured inorder to investigate electric properties in Ethylene Prophylene Rubber for is irradiated C0$^{60}$$\gamma$ ray 0~38.1 Mrad. The value of charge current and the discharging current of the EPR is influenced by C0$^{60}$-$\gamma$- irradiation dose. The charging current and the discharging current of EPR increas, depending on the ratio of degradation. As the irradiatin dose is increased, the peak of residual voltage moves to the slorter time. The properties specific electric constant due to time variation was appeared dispersion by plentiful C0$^{60}$$\gamma$- irradiation dose. The increase of peak in ${\varepsilon}r^{'}$ is attrib uted to the irratiation dose almost proportionally.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.903-910
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• 2014

This study examined the treatment characteristics of hard-to-degrade pollutants such as TCE which are found in organic solvent and cleaning wastewater by nZVI that have excellent oxidation and reduction characteristics. In addition, this study tried to find out the degradation characteristics of TCE by Fenton-like process, in which $H_2O_2$ is dosed additionally. In this study, different ratios of nZVI and $H_2O_2$, such as 1.0 mM : 0.5 mM, 1.0 mM : 1.0 mM, and 1.0 mM : 2.0 mM were used. When 1.0 mM of nZVI was dosed with 1.0 mM of $H_2O_2$, the removal efficiency of TOC was the highest and the first order rate constant was also the highest. When 1mM of nZVI was dosed with 0.5 mM of $H_2O_2$, the first order rate constant and removal efficiency were the lowest. The size of first order rate constant and removal efficiency was in the order of nZVI 1.0 mM : $H_2O_2$ 1.0 mM > nZVI 1.0 mM : $H_2O_2$ 2.0 mM > nZVI 1.0 mM : $H_2O_2$ 0.5 mM > $H_2O_2$ 1.0 mM > nZVI 1.0 mM. It is estimated that when 1.0 mM of nZVI is dosed with 1.0 mM of $H_2O_2$, $Fe^{2+}$ ion generated by nZVI and $H_2O_2$ react in the stoichiometric molar ratio of 1:1, thus the first order rate constant and removal efficiency are the highest. And when 1.0 mM of nZVI is dosed with 2.0 mM of $H_2O_2$, excessive $H_2O_2$ work as a scavenger of OH radicals and excessive $H_2O_2$ reduce $Fe^{3+}$ into $Fe^{2+}$. As for the removal efficiency of TOC in TCE by simultaneous dose and sequential dose of nZVI and $H_2O_2$, sequential dose showed higher first order reaction rate and removal efficiency than simultaneous dose. It is estimated that when nZVI is dosed 30 minutes in advance, pre-treatment occurs and nanoscale $Fe^0$ is oxidized to $Fe^{2+}$ and TCE is pre-reduced and becomes easier to degrade. When $H_2O_2$ is dosed at this time, OH radicals are generated and degrade TCE actively.

• The Korean Journal of Pain
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• v.5 no.1
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• pp.29-36
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• 1992

This study was objected to evaluate clinical progressions about both the degree of pain relief and the occurrence of morphine tolerance while the epidural analgesia with low dose of morphine, bupivacaine and antidepressant continued repeatedly at every 5 day intervals of the constant-rate infusion(0.5 ml/hr, 60 ml capacity). The subjects were divided to 56 cancer and 36 non-cancer patients who failed to respond to palliative treatments. Before the relief of pain, the pain severity was moderate(10%) and severe(90%). The dose escalation of morphine noted to 11(20%)patients in cancer pain and to one(5%) case only in non-cancer. During the epidural analgesia, the effect of pain relief was moderate(11%) and good(89%). It suggest that the morphine tolerance may be reduced to some degree such as an initial minimum dose of epidural morphine with local anesthetic and antidepressant should be adjusted on an individual basis using the constant-rate infusor, even though rapid dose escalation occurrs in some patients who the diseases progress over a short period of time.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.731-741
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• 2004

The purpose of this study was to evaluate the potential of a gamma ray irradiation to decompose hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in an aqueous solution. The decomposition reaction of RDX by gamma ray irradiation was a first-order kinetic over the applied initial concentrations (10-40mg/L). The dose constant was strongly dependent on the initial concentration of the RDX. The removal of RDX was more efficient at pH below 3 and at pH above 11 than at neutral pH (pH 5-9). The required irradiation dose to remove 99% of the RDX (40mg/L) was 4, 8 and 1 kGy, at pH 2, 7 and 13, respectively. The dose constant was increased by two folds and over twelve folds at pH 2 and 13, respectively, when compared with that at pH 7. When an irradiation dose of 20 kGy was applied, the removal efficiencies of TOC were 80, 57 and 91% at pH 2, 7 and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of RDX and formic acid was detected as an organic byproduct. The results showed that a gamma ray irradiation was an attractive method for the decomposition of RDX in an aqueous solution and it was found that a strong alkaline pH over 12 should be applied to the decomposition reaction of RDX.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.219-226
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• 2010

In order to evaluate a removal characteristic of chloramphenicol, salicylic acid and ketoprofen according to dose of oxidants, $Cl_2$, $O_3$ and $O_3/H_2O_2$ are used as oxidants in this study. In case of that $Cl_2$ is used for oxidizing harmaceuticals, chloramphenicol, salicylic acid and ketoprofen is not removed entirely at $Cl_2$ dose rang of 0.5~5.0 mg/L for 60 min. However, removal tendency of salicylic acid is so obviously at $Cl_2$ dose higher than 1.0 mg/L. In addition, as $Cl_2$ dose and contact time increase, the removal rate of salicylic acid is enhanced. When $O_3$ is used as oxidant, chloramphenicol and ketoprofen is not eliminated at $O_3$ dose range of 0.2~2.0 mg/L. On the contrary, 30~70% of salicylic acid is removed at $O_3$ dose of 1.0~5.0 mg/L. Only 30% removal of salicylic acid is achieved at contact time of 5 min, however, the removal rate is enhanced remarkably at contact time over 10 min. In experiments using $O_3/H_2O_2$ as an oxidant, we can find that $O_3/H_2O_2$ is much more effective than $O_3$ only for removal of 3 pharmaceuticals, and the efficiency is raised according to increase of $H_2O_2$ dose. On reaction rate constant and half-life of 3 pharmaceuticals depending on $Cl_2$, $O_3$ and $O_3/H_2O_2$ dose, experiments using $O_3/H_2O_2$ show that oxidation of pharmaceuticals is less effective as the $H_2O_2/O_3$ ratio increases to above pproximately 1.0 related to reaction rate constant. An oxidation of salicylic acid by $Cl_2$ and $O_3$ particularly has a comparatively high reaction rate constant comparing $O_3/H_2O_2$, and thus salicylic acid is easily eliminated in oxidation processes.

• Journal of Environmental Science International
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• v.31 no.3
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• pp.227-235
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• 2022

In this study, a biodegradation model of based on molecular cellulose was established. It is a mathematical, kinetic model, assuming that two major enzymes randomly break glycosidic bonds of cellulose molecules, and calculates the number of molecules by applying the corresponding probability and degradation reaction coefficients. Model calculations considered enzyme dose, cellulose chain length, and reaction rate constant ratio. Degradation increased almost by two folds with increase of temperature (5℃→25℃). The change of degradation was not significant over the higher temperatures. As temperature increased, the degradation rate of the molecules increased along with higher production of shorter chain molecules. As the reaction rates of the two enzymes were comparative the degree of degradation for any combinations of enzyme application was not affected much. Enzyme dose was also tested through experiment. While enzyme dose ranged from 1 mg/L to 10 mg/L, the gap between real data and model calculations was trivial. However, at higher dose of those enzymes (>15 mg/L), the experimental result showed the lower concentrations of reductive sugar than the corresponding model calculation did. We determined that the optimal enzyme dose for maximum generation of reductive sugar was 10 mg/L.

• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.11-22
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• 1998

The absolute absorbed dose can be determined according to the measurement conditions ; measurement material, detector, energy and calibration protocols. The purpose of this study is to compare the absolute absorbed dose due to the differences of measurement condition and calibration protocols for photon beams. Dosimetric measurements were performed with a farmer type PTW and NEL ionization chambers in water, solid water, and polystyrene phantoms using 6MV photon beams from Siemens linear accelerator. Measurements were made along the central axis of $10{\times}10cm$ field size for constant target to surface distance of 100cm for water, solid water and polystyrene phantom. Theoretical absorbed dose intercomparisons between TG21 and IAEA protocol were performed for various measurement combinations on phantom, ion chamber, and electrometer. There were no significant differences of absorbed dose value between TG2l and IAEA protocol. The differences between two protocols are within $1\%\;while\;the\;average\;value\;of\;IAEA\;protocol\;was\;0.5\%$ smaller than TG2l protocol. For the purpose of comparison, all the relative absorbed dose were nomalized to NEL ion chamber with Keithley electrometer and water phantom, The average differences are within $1\%,\;but\;individual\;discrepancies\;are\;in\;the\;range\;of\;-2.5\%\;to\;1.2\%$ depending upon the choice of measurement combination. The largest discrepancy of $-25\%$ was observed when NEL ion chamber with Keithley electrometer is used in solid water phantom. The main cause for this discrepancy is due to the use of same parameters of stopping power, absorption coefficient, etc. as used in water phantom. It should be mentioned that the solid water phantom is not recommended for absolute dose calibration as the alternative of water, since absorbed dose show some dependency on phantom material other than water. In conclusion, the trend of variation was not much dependent on calibration protocol. However, It shows that absorbed dose could be affected by phantom material other than water.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.93-100
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• 1989

Several combinations of measuring devices and phantoms were studied to measure electron beams. Silicon Pmt junction diode was used to find the dependence of depth dose profile on field size on axis of electron beam Depths of 50, 80 and $90\%$ doses increased with the field size for small fields. For some larger fields, they were nearly constant. The smallest of field sizes over which the parameters were constant was enlarged with increase of the energy of electron beams. Depth dose distributions on axis of electron beam of $10\times10cm^2$ field were studied with several combinations of measuring devices and phantoms. Cylindrical ion chamber could not be used for measurement of surface dose, and was not convenient for measurement of near surface region of 6MeV electron. With some exceptions, parameters agreed well with those studied by different devices and phantoms. Surface dose in some energies showed $4\%$ difference between maximum and minimum. For 18MeV, depths of 80 and $90\%$ doses were considerably shallower by film than by others. Parallel-plate ion chamber with polystyrene phamtom and silicon PN junction would be recommended for measurement of central axis depth dose of electron beams with considerably large field size. It is desirable not to use cylindrical ion chamber for the purpose of measurement of surface dose or near surface region for lower energy electron beam. It is questionable that film would be recommended for measurement of dose distribution of electron with high energy like as 18MeV.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.204-212
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• 1987

Rifampicin is an indispensable drug along with isoniazid for the control of tuberculosis and is usually prescribed as the combination of rifampicin and isoniazid. This paper is attemtped to investigate the interaction of rifampicin and isoniazid. Isoniazid was administered orally at a dose of 30mg/kg of rabbits pretreated with rifampicin 7.5mg/kg, 15mg/kg, and 30mg/kg, respectively twice daily for 9 days. The results are as follows: The blood level and relative bioavailability of isoniazid were decreased significantly (p<0.05) by rifampicin at a dose of 15mg/kg and 30mg/kg. The renal clearance of total isoniazid and ratio of its metabolites to isoniazid were increased significantly (p<0.05) by rifampicin at a dose of 15mg/kg and 30mg/kg. It seemed to be due to enzyme induction by rifampicin. Elimination rate constant ($\beta$) of isoniazid was increased and half life ($t_{1/2$\beta}$) was decreased by rifampicin pretreatment. Dosage regimen of isoniazid after long term administration of rifampicin should be adjusted carefully.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.526-530
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• 2018

Human fingernails were used to estimate the radiation dose via electron paramagnetic resonance measurements of radiation-induced radicals. The limiting factors in this research were mechanically induced electron paramagnetic resonance signals due to the mechanical stress during the preparation of the samples. Therefore, different treatment methods of fingernails were used to reduce the mechanically induced signals. The results demonstrate that the mechanically induced and radiation-induced signals have apparently different microwave power saturation behaviors. In addition, the mechanically induced signal shows a fading evolution over time and reaches a constant value. Chemical treatment using the different reagents showed that the minimum mechanically induced signal was obtained using the dithiothreitol reagent. The dose-response curves of the samples treated with dithiothreitol for 30 minutes demonstrated a greater linearity than those of samples treated for 5 minutes. Therefore, to find an unknown absorbed dose in a fingernail sample using a calibration curve, we recommend adopting the mentioned chemical treatment procedure to reduce the uncertainty.