• Journal of radiological science and technology
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• v.38 no.1
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• pp.23-30
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• 2015

Positron emission tomography scan has been growing diagnostic equipment in the development of medical imaging system. Compare to 99mTc emitting 140 keV, Positron emission radionuclide emits 511 keV gamma rays. Because of this high energy, it needs to reduce radioactive emitting from patients for radio technologist. We searched the external dose rates by changing distance from patients and measure the external dose rates when we used shielder investigate change external dose rates. In this study, the external dose distribution were analyzed in order to help managing radiation protection of radio technologists. Ten patients were searched (mean age: $47.7{\pm}6.6$, mean height: $165.5{\pm}3.8cm$, mean weight: $65.9{\pm}1.4kg$). Radiation was measured on the location of head, chest, abdomen, knees and toes at the distance of 10, 50, 100, 150, and 200 cm, respectively. Then, all the procedure was given with a portable radiation shielding on the location of head, chest, and abdomen at the distance of 100, 150, and 200 cm and transmittance was calculated. In 10 cm, head ($105.40{\mu}Sv/h$) was the highest and foot($15.85{\mu}Sv/h$) was the lowest. In 200 cm, head, chest, and abdomen showed similar. On head, the measured dose rates were $9.56{\mu}Sv/h$, $5.23{\mu}Sv/h$, and $3.40{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.24{\mu}Sv/h$, $1.67{\mu}Sv/h$, and $1.27{\mu}Sv/h$ in 100, 150, and 200 cm on head. On chest, the measured dose rates were $8.54{\mu}Sv/h$, $4.90{\mu}Sv/h$, $3.44{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.27{\mu}Sv/h$, $1.34{\mu}Sv/h$, and $1.13{\mu}Sv/h$ in 100, 150, and 200 cm on chest. On abdomen, the measured dose rates were $9.83{\mu}Sv/h$, $5.15{\mu}Sv/h$, and $3.18{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.60{\mu}Sv/h$, $1.75{\mu}Sv/h$, and $1.23{\mu}Sv/h$ in 100, 150, and 200 cm on abdomen. Transmittance was increased as the distance was expanded. As the distance was further, the radiation dose were reduced. When using shielder, the dose were reduced as one-forth of without shielder. The Radio technologists are exposed of radioactivity and there were limitations on reducing the distance with Therefore, the proper shielding will be able to decrease radiation dose to the technologists.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.73-76
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• 2005

The acaricidal activities of 12 commercial constituents derived from Eugenia caryophyllata leaf oils against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae adults were examined using an impregnated fabric disk application and compared with that of the commercial benzyl benzoate as synthetic acaricide. On the basis of $LD_{50}$ values, the most toxic compound was methyl eugenol ($4.13\;{\mu}g/cm^2$), followed by methyl isoeugenol ($4.19\;{\mu}g/cm^2$), isoeugenol ($4.29\;{\mu}g/cm^2$), eugenol ($4.94\;{\mu}g/cm^2$), and acetyl eugenol ($13.91\;{\mu}g/cm^2$) against D. farinae. In the case of D. pteronyssinus, isoeugenol ($2.93\;{\mu}g/cm^2$) was the most toxic, followed by methyl isoeugenol ($3.28\;{\mu}g/cm^2$), methyl eugenol ($3.87\;{\mu}g/cm^2$), eugenol ($3.92\;{\mu}g/cm^2$), and acetyl eugenol ($7.21\;{\mu}g/cm^2$). These results suggest that D. pteronyssinus may be controlled more effectively by the application of eugenol congeners than D. farinae. In comparison with synthetic acaricides, the acaricidal activities of eugenol, isoeugenol, methyl eugenol, and methyl isoeugenol were about 1.9-2.2 times more toxic than benzyl benzoate. Furthermore, the most toxic constituent against T. putrescentiae was exhibited on eugenol ($10.11\;{\mu}g/cm^2$), followed by methyl eugenol ($38.67\;{\mu}g/cm^2$) and acetyl eugenol ($70.09\;{\mu}g/cm^2$), but no activity was observed for isoeugenol and methyl isoeugenol. The results suggested that eugenol congeners may be useful as a new source for selective control of house dust mites and stored food mites.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.122-126
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• 1994

Corrosion of brass coated steel cords in the acetonitrile solution of sulfenamide derivatives, N-Cyclohexylbenzothiazole-2-sulfenamide (CBTS), N,N'-Dicyclohexylbenzothiazole-2-sulfenamide (DCBS), N-tert-Butylbenzothiazole-2-sulfenamide (TBBS), N-tert-Amylbenzothiazole-2-sulfenamide (TABS), and N-Oxydiethylbenzothiazole-2-sulfenamide (OBTS) was investigated by potentiostatic anodic and cathodic polarization (Tafel plot), DC polarization resistance, and AC impedance measurements. The corrosion current densities and rates are 1.236 ${\mu}A /cm^2$ and 0.655 MPY for CBTS; 1.881 ${\mu}A/cm^2$ and 0.988 MPY for DCBS; 2.367 ${\mu}A/cm^2$ and 1.257 MPY for TBBS; 3.398 ${\mu}A /cm^2$ and 1.809 MPY for TABS, respectively. OBTS among derivatives under study shows the lowest corrosion density (0.546 ${\mu}A /cm^2$) and the slowest corrosion rate (0.288 MPY). Also, the charge transfer resistances and the double layer capacitances are 275.21 $k{\Omega}{\cdot}cm^2$ and 7.0 ${\mu}F{cdot}cm^{-2}$ for CBTS; 14.24 ${\mu}F{\cdot}cm^2$ and 26 ${\mu}F{\cdot}cm^{-2}$ for DCBS; 54.15 $k{\Omega}{\cdot}cm^2$ and 26 ${\mu}F{\cdot}cm^{-2}$ for TBBS; 0.96$k{\Omega}{\cdot}cm^2$ and 83 ${\mu}F{\cdot}cm^{-2}$ for TABS, respectively. The weaker the electron donating inductive effect of derivatives is and the smaller the effect of steric hindrance is, the more the corrosion of brass coated steel cords in the acetonitrile solution of sulfenamide derivatives is prevented. The above results agree with that observed in the field of tire industry.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.269-276
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• 2010

This study attempts to propose ways to optimize and improve the period of hospitalization for the radioiodine treatment by calculating the dose rate of patients treated with high-dose radioiodine by distance and time slot. As a result, 24 hours after the patient was treated with 100 mCi high-dose iodine, the dose rate was attenuated to $1,035{\mu}Sv/hr$ at the navel, to $109{\mu}Sv/hr$ at 50 cm, and to $33{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 150 mCi high-dose iodine, the dose rate was attenuated to $637{\mu}Sv/hr$ at the navel, to $100{\mu}Sv/hr$ at 50 cm, and to $40{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 180 mCi high-dose iodine, the dose rate was attenuated to $1,251{\mu}Sv/hr$ at the navel, $140{\mu}Sv/hr$ at 50 cm, and to $56{\mu}Sv/hr$ at 100 cm. In light of the current criterion for discharge recommended by the US Nuclear Regulatory Commission being $70.4{\mu}Sv/hr$, the present study indicates earlier discharge is feasible by applying a new scheme. This suggests that the proposed scheme in this study will help to solve the problem of shortage of treatment beds with the increasing trend of patients with thyroid cancer taken into consideration.

• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.413-419
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• 2001

This study investigated pH values and EC changes of rainfall and stemflow were investigated for 5 tree species such as Pinus koraiensis, P. densiflora, Larix leptolepis, Quercus variabilis and Q. mongolica in the Experiment Forests, College of Forest Science, Kangwon National University. The results were as follows; 1. Mean month pH values of stemflow were much lower than those of rainfall. Among tree species, pH values of the coniferous such as P. densiflora, P. koraiensis and L. leptolepis were lower those of the deciduous such as Q. mongolica and Q. variabilis. Mean month pH values of stemflow ranged from 3.23 to 5.03 (average : 4.23) for P. koraiensis, 3.57 to 5.16 (average : 4.36) for P. densiflora, 3.41 to 6.69 (average : 4.45) for L. leptolepis, 3.86 to 6.11 (average : 4.70) for Q. variabilis and 4.39 to 6.13 (average : 5.18) for Q. mongolica. 2. Mean month EC of the coniferous species was 1.5 to 2 times higher than that of the deciduous species. Mean month EC of stemflow for P. koraiensis, P. densiflora, L. leptolepis, Q. variabilis and Q. mongolica was ranged from 29.0 to $946.5{\mu}S/cm$(average : $258.5{\mu}S/cm$), 18.6 to $907.5{\mu}S/cm$(average : $220.3{\mu}S/cm$), 27.0 to $918.0{\mu}S/cm$(average : $216.2{\mu}S/cm$), 16.5 to $301.6{\mu}S/cm$(average : $125.4{\mu}S/cm$) and $25.2{\sim}225.7{\mu}S/cm$(average : $101.5{\mu}S/cm$), respectively. 3. Average pH values and EC were highly variable according to season. Average pH values appeared lower in spring than those in summer and autumn, but EC appeared higher in spring than those lower in summer and autumn. 4. According to precipitation, there was little difference in and pH values of stemflow the coniferous and the deciduous showed low pH valuess in the case of less than 50mm precipitation. However, EC of stemflow showed a difference depending on the precipitation, and EC of the coniferous and the deciduous was high more than $100{\mu}S/cm$ at the precipitation of less than 50mm.

• Journal of Forest and Environmental Science
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• v.16 no.1
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• pp.82-92
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• 2000

The pH, EC and anion of stemflow in Quercus mongolica and Q. variabilis were surveyed and analyzed in order to examine the relationship between watershed conservation function and flood control function of forest in quality and quantity in the Experiment Forests. College of Forest Sciences, Kangwon National University. The results were as follows: 1. pH values of rainfall ranged from 4.47 to 6.55(average: 5.39), and pH values of throughfall ranged from 4.07 to 6.25(average 5.45) for Q. mongolica and from 4.34 to 6.57(average : 5.62) for Q. variabilis, and thus pH values were not different between these two species. Also, pH values of stemflow from Q. mongolica ranged from 4.08 to 6.13(average 5.17) and those of stemflow from Q. variabilis ranged from 3.62 to 6.11(average : 4.68), and pH values of rainfall gave little influence on pH values of stemflow. But, pH values of stemflow in Q. mongolica and Q. variabilis appeard significantly lower in spring and than those in summer and autumn. 2. EC of rainfall was $3.0{\sim}62.6{\mu}s/cm$(average: $18.8{\mu}s/cm$), and EC of throughfall was $5.4{\sim}85.0{\mu}s/cm$(average : $25.1{\mu}s/cm$) for Q. mongolica and $5.0{\sim}253.0{\mu}s/cm$(average : $31.2{\mu}s/cm$) for Q. variabilis. Also, EC of stemflow from Q. mongolica ranged from 9.5 to $500.0{\mu}s/cm$(average : $81.8{\mu}s/cm$) and that of stemflow from Q. variabilis ranged from 11.5 to $534.5{\mu}s/cm$(average : $80.2{\mu}s/cm$). Seasonal EC of rainfall had little variation in the range of 20 to $30{\mu}s/cm$: EC of stemflow showed more than $100{\mu}s/cm$ from March to April and about $30{\mu}s/cm$ in summer period. Seasonal EC of stemflow varied so much and appeared high again from October to November. 3. $Cl^-$, $NO_3{^-}$ and $SO_4{^{2- }}$ concentrations of rainfall and throughfall were from 1 to 15ppm. and $PO_4{^{2- }}$ concentrations showed 0.57ppm and 0.23ppm in rainfall, 0.08ppm in Q. mongolica and 0.14ppm, 0.12ppm and 1.19ppm in Q. variabilis. Also, $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$ concentrations of stemflow were relatively higher than rainfall, and showed differences among seasons. $PO_4{^{2-}}$ concentration of rainfall and throughfall were not possible to observe, but $PO_4{^{2-}}$ concentrations of stemflow ranged from 0.08 to 31.99ppm(average : 3.22ppm) for Q. mongolica and that of stemflow ranged from 0.06 to 12.28ppm(average : 1.93ppm) for Q. variabilis.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.11
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• pp.63-70
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• 1999

A PLT(10) thin film has been deposited on $Pt/TiO_2/SiO_2/Si$ substrate by sol-gel method, and its switching characteristics have been investigated with various top electrode areas, input pulse voltages and loan resistances. As the external input pulse voltage increases from 2V to 5V, the switching time decreases from $0.49{\mu}s$ to $0.12{\mu}s$. The activation energy ($E_a$) obtained from the relations between the switching time and the applied pulse voltage is evaluated as 209kV/cm. The switched charge densities at 5V obtained from the hysteresis loop and the polarization switching are $11.69{\mu}C/cm^2$ and $13.02{\mu}C/cm^2$, respectively, which agree relatively well with each other and show the difference of 10%. When the top electrode area increases from TEX>$3.14{\times}10^{-4}cm^2$ to $5.03{\times}10^{-3}cm^2$ and the load resistance increases from 50${\Omega}$ to 3.3$k{\Omega}$, the switching time increases from $0.12{\mu}s$ to $1.88{\mu}s$ and from $0.12{\mu}s$ to $9.7{\mu}s$, respectively. These switching characteristics indicate that PLT(10) thin film can be well applied in nonvolatile memory devices.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.159-165
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• 2010

Purpose: Positron emission tomography scan has been growing diagnostic equipment in the development of medical imaging system. Compare to $^{99m}Tc$ emitting 140 keV, Positron emission radionuclide emits 511 keV gamma rays. Because of this high energy, it needs to reduce radioactive emitting from patients for radiotechnologist. We searched the external dose rates by changing distance from patients and measure the external dose rates when we used shielder investigate change external dose rates. In this study, the external dose distribution were analyzed in order to help managing radiation protection of radiotechnologists. Materials and Methods: Ten patients were searched (mean age: $47.7{\pm}6.6$, mean height: $165.5{\pm}3.8$ cm and mean weight: $65.9{\pm}1.4$ kg). Radiation were measured on the location of head, chest, abdomen, knees and toes at the distance of 10, 50, 100, 150 and 200 cm. Then, all the procedure was given with a portable radiation shielding on the location of head, chest and abdomen at the distance of 100, 150 and 200 cm and transmittance was calculated. Results: In 10 cm, head (105.40 ${\mu}Sv/h$) was the highest and foot (15.85 ${\mu}Sv/h$) was the lowest. In 200 cm, head, chest and abdomen showed similar. On head, the measured dose rates were 9.56 ${\mu}Sv/h$, 5.23 ${\mu}Sv/h$, and 3.40 ${\mu}Sv/h$ in 100, 150 and 200 cm respectively. When using shielder, it shows 2.24 ${\mu}Sv/h$, 1.67 ${\mu}Sv/h$, and 1.27 ${\mu}Sv/h$ in 100, 150 and 200 cm on head. On chest, the measured dose rates were 8.54 ${\mu}Sv/h$, 4.90 ${\mu}Sv/h$, 3.44 ${\mu}Sv/h$ in 100, 150 and 200 cm, respectively. When using shielder, it shows 2.27 ${\mu}Sv/h$, 1.34 ${\mu}Sv/h$, and 1.13 ${\mu}Sv/h$ in 100, 150 and 200 cm on chest. On abdomen, the measured dose rates were 9.83 ${\mu}Sv/h$, 5.15 ${\mu}Sv/h$ and 3.18 ${\mu}Sv/h$ in 100, 150 and 200cm respectively. When using shielder, it shows 2.60 ${\mu}Sv/h$, 1.75 ${\mu}Sv/h$ and 1.23 ${\mu}Sv/h$ in 100, 150 and 200 cm on abdomen. Transmittance was increased as the distance was expanded. Conclusion: As the distance was further, the radiation dose were reduced. When using shielder, the dose were reduced as one-forth of without shielder. The Radio technologists are exposed of radioactivity and there were limitations on reducing the distance with Therefore, the proper shielding will be able to decrease radiation dose to the radiotechnologists.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.29-37
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• 1999

In this study, we have prepared PLT thin films having various La concentrations by using sol-gel method and studied on the effect of La concentration on the electrical properties of PLT thin films. As the La concentration increases from 5mol% to 28mol%, the dielectric constant at 10kHz increases from 428 to 761, while the loss tangent decreases from 0.063 to 0.024. Also, the leakage current density at 150kV/cm has a tendency to decrease from 6.96${\mu}A/cm^2$ to 0.79${\mu}A/cm^2$. In the result of hysteresis loops of PLT thin films, the remanent polariation and the coercive field decrease from 9.55${\mu}C/cm^2$ to 1.10${\mu}C/cm^2$ and from 46.4kV/cm to 13.7kV/cm, respectively. With the result of the fatigue test on the PLT thin films, we have found that the fatigue properties are improved remarkably as the La concentration increases from 5 mol% to 28mol%. In particular, the PLT28) has paraelectric phase and its charge storage clensity and leakage current density at 5V are 134fC/${\mu}cm^2$ and 1.01${\mu}A/cm^2$, respectively. The remanent polarization and coercive field of the PLT(10) film are 6.96${\mu}C/cm^2$ and 40.2kV/cm, respectively. After applying of $10^9$ square pulses with ${\pm}5V$, the remanent polarilzation of the PLT(10) film decreases about 20% from the initial state. In the results, we conclude that the 10mol% and the 28mol% La doped PLT thin films are very suitable for the capacitor dielectrics of new generation of DRAM and NVFRAM respecitively.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.3
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• pp.16-26
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• 2012

Objectives: This study was performed to evaluate effects of Cordyceps militaris(CM) on osteoclast differentiation and its related gene expression. Methods: We used mouse myeloid cells RAW 264.7 stimulated by receptor activator of nuclear factor kappa-B ligand(RANKL) to induce osteoclast differentiation. There are four groups of which RAW 264.7 cells are not stimulated by RANKL (Normal), stimulated by RANKL without CM(Control), stimulated by RANKL with 0.1 ${\mu}g/ml$ of CM(CM 0.1), stimulated by RANKL with 1 ${\mu}g/ml$ of CM(CM 1). Osteoclastogenesis was measured by counting Tartrate-resistant acid phosphatase-positive multinucleated cells [TRAP(+) MNC]. RT-PCR was performed to evaluate the inhibitory effect of CM on gene expression(TRAP, AKT1, JNK1, NFATc1, c-Fos, MITF). Results: 1. CM decreased the number of TRAP(+) osteoclast in RANKL-stimulated RAW 264.7 cell at the concentration of 0.1 ${\mu}g/ml$ and 1 ${\mu}g/ml$. 2. CM decreased the expression of TRAP in osteoclast at the concentration of 1 ${\mu}g/ml$. 3. CM decreased the expression of AKT1, JNK1 in osteoclast at the concentration of 1 ${\mu}g/ml$. 4. CM didn't affect the expression of NFATc1, c-Fos, MITF in osteoclast. Conclusions: Cordyceps militaris has inhibitory effects on osteoclast differentiation and its related gene expression. These results suggest that Cordyceps militaris has a potential as a treatment of osteoporosis.