• The Korean Journal of Nuclear Medicine
• /
• v.28 no.1
• /
• pp.133-140
• /
• 1994

Recently, there are many considerations and studies on biological effects of radiations in radiation workers, as well as in accidentally or therapeutically irradiated persons. The most practical and reliable method of dosimetry for radiation accidents is the scoring of gross chromosomal aberrations in human lymphocytes (Ydr) as a biological dosimetry. By the way, although usual doses of $^{131}I$ administered therapeutically for thyroid cancer are ranging from 100 mCi to 200 mCi, there are differences of absorbed doses and Ydr, ranging from 0.004 to 0.04, on equally administered $^{131}I$ due to variations in metabolic characteristics, stage of tumors and physical status of subjects. In this study, We exert to obtain the dose-response relationships of $^{131}I$, as a good guide to evaluating acute effects of accidental irradiations and radiation induced leukemia or solid tumor, by in vitro induction of chromosomal aberrations. we studied the relationship between radiation dose (D) and the frequency of chromosomal aberrations (Ydr) obserbed in peripheral lymphocytes that were irradiated in vitro with $^{131}I$ at doses ranging from 0.05 to 6.00 Gy. By scoring cells with unstable chromosomal aberrations (dicentric chromosomes and ring chromosomes) we obtained this linear-quadratic dose response equation Ydr=0.064351 $D^2$-0.13143 D+0.045684 This dose-response relationship may be useful for evaluating acute and chronic $^{131}I$ induced biological effects.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.3
• /
• pp.349-354
• /
• 2000

Abstract A facultative alkalophilic gram-negative Vibrio metschnikovii strain RH530, isolated from the wastewater, produced several alkaline proteases (VAP) including six alkaline serine proteases and a metalloprotease. From this strain, high yielding YAP mutants were isolated by NTG treatment. The isolated mutant KS1 showed nine times more activity than the wild-type after optimization of the culture media. The production was regulated by catabolite repression when glucose was added to the medium. The effects of several organic nitrogen sources on the production of the YAP were investigated to avoid catabolite repression. The combination of 4% wheat gluten meal (WGM), 1.5% cotton seed flour (eSF), and 5% soybean meal (SBM) resulted in the best production when supplemented with 1% NaCl. The YAP showed a resistance to surfactants such as $sodium-{\alpha}-olefin$ sulfonate (AOS), polyoxy ethylene oxide (POE), and sodium dodecyl sulfate (SDS), yet not to linear alkylbenzene sulfonate (LAS). However, the activity of the YAP was restored completely when incubated with LAS in the presence of POE or $Na_2SO_4$. The YAP was stable in a liquid laundry detergent containing 6.6% SLES (sodium lauryl ether sulfate), 6.6% LAS, 19.8% POE, and stabilizing agents for more than two weeks at $40^{\circ}C$, but the stability was sharply decreased even after 1 day when incubated at $60^{\circ}C$. A washing performance test with the YAP exhibited it to be a good washing power by showing 51 % and 60% activity at $25^{\circ}C{\;}and{\;}40^{\circ}C$, respectively, thereby indicating that the YAP also has a good detergency at a low temperature. All the results suggest that the YAP produced from the mutant strain KSI has suitable properties for use in laundry detergents.rgents.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.11
• /
• pp.1783-1791
• /
• 2013

This study is investigated to evaluate the enhancement of antioxidant compound and activity of rough rice with different germination periods and high pressure treatment. The subject was germinated at $37^{\circ}C$ for 6 days (HP0), and then the germinated rough rice were subjected to 30 MPa for 24 hr (HP24) and 48 hr (HP48), respectively. HP0, HP24 and HP48 samples were prepared and extracted with 80% ethanol. The highest total polyphenol contents (5.15 mg/g) occurred in treating at HP48 after germination for 5 days. The total phenolic acid contents including gallic acid, chlorogenic acid, catechin, ${\rho}$-coumaric acid, ferulic acid, salicylic acid, naringin, myricetin, trans-cinnamic acid, naringenin and kaempferol increased from $37.26{\sim}204.32{\mu}g/g$ at HP0 to $77.29{\sim}283.05{\mu}g/g$ at HP48. In antioxidant activity analyses, HP48 extracts showed higher values in ABTS and DPPH radical scavenging activity, reducing power, and $Fe^{2+}$ iron chelating effect than those of the HP24 and HP0 extracts. These results suggest that the combined treatment of high pressure treatment and germination process efficiently enhanced antioxidant compound and activity of rough rice.

• Analytical Science and Technology
• /
• v.12 no.2
• /
• pp.125-129
• /
• 1999

Portable-type two electrode system for the determination of highly concentrated hydrogen peroxide (10-75%) has been studied. The electrode body was made with teflon rod (length=10 cm, diameter=1.5 cm) to withstand the highly corrosive power of hydrogen peroxide. Glass carbon rod (diameter=3 mm) was used as the working electrode and a carbon cylinder (i.d.=5 mm; o.d.=9 mm) was used as counter electrode. The applied voltage for the determination of $H_2O_2$ was 0.8 V. Diluting the highly concentrated samples taken from the industrial batch to 10% or less, it was possible to make quantitative determinations, while eliminating the interference from the stabilizer contained in the sample and preventing the surface of the electrode from oxidative corrosion. Employing hydrogen peroxide permeable membrane (teflon membrane${\leq}100{\mu}m$) for the electrode system, it was possible to measure the content of $H_2O_2$ in highly concentrated samples directly, quantitatively and reproducibly with no extra dilution step. However, it was necessary to change the internal electrolyte frequently to maintain the analytical performance of the electrode.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.11
• /
• pp.239-249
• /
• 2019

Recently, the Korean government has implemented a policy to expand renewable energy sources. Large-scale PV systems are being actively interconnected with the distribution system. On the other hand, when a large-scale PV system is installed and operated, the customer voltages could violate the allowable voltage limit due to reverse power flow of the PV system. To overcome these problems, an enhancement method for hosting the capacity of the PV system in a distribution system is being actively conducted. Therefore, to improve the hosting capacity of the PV system, this paper proposes a model of a reconfiguration of the distribution system, which is composed of three sections and three connections based on PSCAD/EMTDC S/W, and proposes an evaluation algorithm for the feeder reconfiguration to maximize an adaption of the PV system. In addition, this paper presents the optimal method of the feeder reconfiguration section to evaluate the maximum capacity of the PV system to keep customer voltages within the allowable voltage limits based on various operation scenarios, such as the capacity of a PV system and section of feeder reconfiguration. From the simulation results based on the PSCAD/EMTDC modeling and evaluation algorithm, it was confirmed that they are a useful and practical tool to enhance hosting the capacity of a PV system in a distribution system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.10
• /
• pp.590-597
• /
• 2018

Recently, the installation of PV systems has been increasing due to the worldwide interest in eco-friendly and renewable solar energy. On the other hand, the output power of PV systems is influenced strongly by the surrounding weather conditions. In addition, the entire operation efficiency of PV systems may be decreased considerably even if only some of the PV modules are in the shade. In other words, the existing control method at which strings with modules in series are connected to an inverter may be not operated in the case that the string voltage in partial shade is lower than the operating range of the grid connected inverter. To overcome these problems, this paper proposes an operation efficiency improvement device of a PV system using a Li-ion battery, which can compensate for the voltage of each string in the PV system when it is partially shaded. In addition, this paper presents the modeling of the operation efficiency improvement device, including PV strings, Li-ion battery and a 3-Phase grid inverter based on the PSIM S/W. From the simulation results, it was confirmed that the proposed control method can improve the operating efficiency of PV systems by compensating for the string voltage with partial shade.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.20-28
• /
• 2020

According to the 3020 RE (renewable energy) policy of the Korean Government, distributed generators, including PV (photovoltaic) and WP (wind power) systems, have been installed and operated in distribution systems. On the other hand, if large-scale PV systems are interconnected in a distribution system, the spread of PV systems may be postponed due to a reduction of the hosting capacity in PV systems because of the over-voltage phenomena at the customer end by violating the allowable voltage limits. Under these circumstances, this paper proposes an evaluation algorithm of the hosting capacity of a PV system based on the LDC (line drop compensation) method of SVR (step voltage regulator) to improve the hosting capacity when large-scale PV systems are installed in a distribution system. Moreover, this paper presents a modeling of a complex distribution system, which is composed of a large-scale PV system and SVR with the LDC method using PSCAD/EMTDC. The simulation results confirmed that the proposed algorithm and modeling are useful and practical tools for improving the hosting capacity of a PV system because the customer voltages are maintained within the allowable voltage limits even if 6.5[MW] of the PV system is installed in a distribution system with the LDC method of SVR.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.17-26
• /
• 2018

If a photovoltaic (PV) system is installed in a primary feeder interconnected with the PV system, bi-directional power flow can occur, and then, the magnitude and direction of the fault current can change, depending on the fault location and point of common coupling (PCC) of the PV system, and the time current curve (TCC) cannot be properly coordinated between protection devices. Also, it is difficult to obtain a proper time interval for protection devices because the conventional setting approach is applied, even though the PV system is installed and operating. Therefore, this paper presents three operation modes considering the operational conditions of the PV system to obtain setting values for protection devices. Based on the mode, this paper proposes an algorithm to calculate the optimal protection coordination time interval according to the introduction capacity of the PV system. In addition, this paper performs modelling of a distribution system with the PV system and protection devices by using Off-DAS S/W, and analyzes the characteristics of the time interval between the protection devices, such as substation relays, reclosers, customer relays, and PV customer relays. The simulation results confirmed that the proposed operational modes and setting-value algorithms are useful and effective for protection coordination in a distribution system for a PV system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.9-17
• /
• 2020

Recently, RES (renewable energy source) projects have been spreading all over the world as an alternative to solve the shortage of energy and environmental problems caused by fossil fuel consumption. The Korean government also supported the policy and demonstration project to increase the proportion of renewable energy to 63.8[GW] until 2030, which is 20[%] of the total power generation. On the other hand, output loss of a PV array can occur when the surrounding high-rise buildings and trees shade a PV array. Therefore, this paper proposes an algorithm to improve the output loss of a PV array, which electrically changes a circuit configuration of PV modules by wiring and switching devices. Furthermore, this study modeled a PV system based on PSIM S/W, which was composed of a PV array, a circuit configuration device, and a grid-connected inverter. From the simulations results with the modeling and test device, the existing method showed no output when 50% of the shade occurs in PV modules. In contrast, the proposed method could produce the output because the voltage in the PV module could be restored to 246[V], and the operation efficiency of the PV system could be improved by the operation algorithm of the circuit configuration device.

• Journal of Trauma and Injury
• /
• v.23 no.1
• /
• pp.29-37
• /
• 2010

Purpose: Controversy exists regarding whether pediatric blunt abdominal trauma patients with microscopic hematuria should undergo radiographic evaluation. Adult patients have indications such as shock and deceleration injury. This study was conducted to suggest indications for the use of CT to detect significant renal injury in pediatric blunt abdominal trauma patients with microscopic hematuria. Methods: From January 2005 to December 2009, patients less than 18 years of age with blunt abdominal trauma and microscopic hematuria who had undergone CT were included in this retrospective study. We analyzed the correlation between microscopic hematuria, shock, deceleration injury, and American Association for the Surgery of Trauma (AAST) renal injury grade. Patients were divided into two groups: the insignificant renal injury group (AAST grade 1) and the significant renal injury group (AAST grades 2-5). We compared age, gender, mechanism of injury, degree of microscopic hematuria, evidence of shock, presence of deceleration injury, and associated injuries between the two groups. We analyzed the effect of each of the above each factors on renal injury by using a logistic regression analysis. Results: Forty-three children were included, and the median age was 15 years. Five children had a significant renal injury. No significant differences, except age and microscopic hematuria (more than 30 red blood cells per high power field (RBC/HPF), p = 0.005) existed between the insignificant and the significant injury groups. A positive correlation existed between renal injury and microscopic hematuria (rho = 0.406, p = 0.007), but renal injury was not correlated with shock and deceleration injury. In the multivariate regression analysis, microscopic hematuria was the only factor correlated with renal injury (p = 0.042). Conclusion: If a microscopic hematuria of more than 30 RBC/HPF exists, the use of CT should be considerd, regardless of shock and deceleration injury to detect significant renal injury in pediatric blunt abdominal trauma patients.