• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.31-39
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• 2016

Background: It is necessary to consider the overall countermeasure for analysis of nuclear activities according to the increase of the nuclear facilities like nuclear power and reprocessing plants in the neighboring countries including China, Taiwan, North Korea, Japan and South Korea. South Korea and comprehensive nuclear-test-ban treaty organization (CTBTO) are now operating the monitoring instruments to detect radionuclides released into the air. It is important to estimate the origin of radionuclides measured using the detection technology as well as the monitoring analysis in aspects of investigation and security of the nuclear activities in neighboring countries. Materials and methods: A three-dimensional forward/backward trajectory model has been developed to estimate the origin of radionuclides for a covert nuclear activity. The developed trajectory model was composed of forward and backward modules to track the particle positions using finite difference method. Results and discussion: A three-dimensional trajectory model was validated using the measured data at Chernobyl accident. The calculated results showed a good agreement by using the high concentration measurements and the locations where was near a release point. The three-dimensional trajectory model had some uncertainty according to the release time, release height and time interval of the trajectory at each release points. An atmospheric dispersion model called long-range accident dose assessment system (LADAS), based on the fields of regards (FOR) technique, was applied to reduce the uncertainties of the trajectory model and to improve the detective technology for estimating the radioisotopes emission area. Conclusion: The detective technology developed in this study can evaluate in release area and origin for covert nuclear activities based on measured radioisotopes at monitoring stations, and it might play critical tool to improve the ability of the nuclear safety field.

• Journal of Food Hygiene and Safety
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• v.31 no.5
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• pp.327-334
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• 2016

This study was conducted to establish the standard method for the contents of biotin in milk formulas. To optimize the method, we compared several conditions for liquid extraction, purification and instrumental measurement using spiked samples and certified reference material (NIST SRM 1849a) as test materials. LC-MS/MS method for biotin was established using $C_{18}$ column and binary gradient 0.1% formic acid/acetonitrile, 0.1% formic acid/water mobile phase is applied for biotin. Product-ion traces at m/z 245.1 ${\rightarrow}$ 227.1, 166.1 are used for quantitative analysis of biotin. The linearity was over $R^2=0.999$ in range of $5{\sim}60{\mu}g/L$. For purification, chloroform was used as a solvent for eliminating lipids in milk formula. The linearity was over 0.999 in range of 5~60 ng/mL. The detection limit and quantification limit were 0.10, 0.31 ng/mL. The accuracy and precision of LC-MS/MS method using CRM were 103%, 2.5% respectively. Optimized methods were applied in sample analysis to verify the reliability. All the tested milk formulas were acceptable contents of biotin compared with component specification and standards for nutrition labeling. The standard operating procedures were prepared for biotin to provide experimental information and to strengthen the management of nutrient in milk formula.

• Journal of Animal Environmental Science
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• v.14 no.2
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• pp.129-138
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• 2008

This study was carried out to investigate the operating characteristics, water balance and chemical properties of compost during the composting with pig slurry on-farm trial. The composting plant with sawdust pile filteration was done in a forced aeration inside a house and equipped with a turning machine moving on a rails. The composting pit was 4.6m wide, 53m long and the maximum height was 2m. A field scale aerobic composting facility was tested the composting efficiency of high moisture pig slurry. The sawdust materials remained 6 months. Pig slurry was added to compost pile every other day during 6 months run. The temperature in compost pile and compost house, and input and output of moisture were measured during composting process. The result are summarized as follows; 1. The temperature of compost was varied in range of at $22.4^{\circ}C{\sim}71.1^{\circ}C$. After turning, the composting temperature decreased to $50^{\circ}C{\sim}36^{\circ}C$ during $3{\sim}5$ hours, and then raised to $64.5^{\circ}C$ 2. The temperature of compost house was maintained $20^{\circ}C{\sim}30^{\circ}C$, and relative humidity was varied in range of $50{\sim}99%$. 3. BOD, CODcr and SS of leachate water was reduced 89.5%, 81.2%, 97.5%, respectively. 4. The content of heavy metal in the final compost was lower those of Korea standards. 5. The amount of effluent was 10.2%. Total evaporation during composting Period were 74.8%. The amount of slurry per $1m^3$ sawdust was $3.16m^3$ without treatment of effluent output.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.128-132
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• 2010

Purpose: Nuclear medicine general operation room is radioactive control room which is used for the handling of radioisotope(R.I). Radioactive contamination materials must be under control and separated from general trash. With this experiments, we want to actively suggest the guideline of controling and operating radioactive contamination materials by measuring contamination degree and analyzing the causes which is not realized so far. Materials and Methods: Materials are selected from Oct. 2009 to March. 2010. salines which are used for labelling radiophamaceuticals and generator cap, saline needle cap, $^{99m}Tc$-needle cap saline vial which is generated from $^{99}Mo$/$^{99m}Tc$ generator. After measuring each surface contamination degree by survey meter, mean value and standard deviation one were solved out. Results: In result, After measuring surface contamination degree, radioactivity of saline for labelling radiophamaceuticals showed $14429{\pm}26378$ cpm (p<0.05) and in measured generators, foreign imported things showed that generator cap : $9{\pm}21$ cpm, saline vial : $17{\pm}28$ cpm. saline needle cap : $35{\pm}66$ cpm, $^{99m}Tc$-needle cap : $9{\pm}21$ cpm, saline vial $13{\pm}28$ cpm. domestic things showed that generator cap : $22852{\pm}52545$ cpm, saline needle cap : $87367{\pm}109711$ cpm, $^{99m}Tc$-needle cap : $9008{\pm}10459$ cpm, saline vial : $186416{\pm}158196$ cpm (p<0.05). Conclusion: The saline which is used for labelling, exceeded 1/10 of maximum permissible range. this is generated from radiophamaceuticals dilution procedure. and In generators, radioactive value of foreign import things showed closely background value. but which of domestic thing showed that exceeded more than 1000 values 1/10 of maximum permissible range. the causes of that is domestic generator is contaminated in manufacturing procedure. So, to dispose radioactive contamination materials which is could betaken out of, the control and operation must be radical under controlled by radioactive measuring, recording and equipping of its own. if this is kept well, we can prevent surely that radioactive waste could be disposed like as general trash.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.3
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• pp.640-658
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• 1996

The purpose of this study was to examine the mechanism of improving acid resistance of Nd-YAG laser irradiated tooth enamel and determine the most effective energy density for improving acid resistance. The bovine tooth enamel were lased with a pulsed Nd-YAG laser. The energy densities of exposed laser beam were varied from 10 to $70\;J/cm^2$. To investigate the degree of improving acid resistance by irradiation, all the samples were submerged to demineralize in 0.5 N $HClO_4$ solution for 1 minute. After 1 minute, 0.05 % $LaCl_3$ was added to the solution for interrupting the demineralization reaction. The amounts of dissolved calcium and phosphate in the solution were measured by using an atomic absorption spectrophotometer and the UV/VIS spectrophotometer, respectively. To examine the mechanism of improving acid resistance, X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy were taken. The X-ray diffraction pattern of the samples were obtained in the $10^{\circ}{\sim}80^{\circ}2{\theta}$ range with $Cu-K{\alpha}$ radiation using M18HF(Mac Science Co.) with X-ray diffractometer operating at 40 KV and 300 mA. The infra-red spectra of the ground samples in 300 mg KBr pellets 10 mm diameter were obtained in the $4000cm^{-1}\;to\;400cm^{-1}$ range using JASCO 300E spectrophotometer. The scanning electron microscopy was carried out using JSM6400(JEOL Co.) with $500{\sim}2000$ times magnification. The results were as follow 1. The concentration of calcium dissolved from laser irradiated enamel with $50J/cm^2$ was significantly lesser than that of unlased control group (p<0.05) 2. From the result of the X-ray diffraction analysis, $\beta$-TCP, which increases acid solubility, was identified in lased enamel but the diffraction peaks of (002) and (004) became sharp with increasing energy density of laser irradiation. This means that the crystals in lased samples were grown through the c-axis and subsequently, the acid solubility of enamel decreased. 3. The a-axis parameter was slightly increased by laser irradiation, whereas the c-axis parameter was almost constant except for a little decrease at $50J/cm^2$. 4. In the infra-red spectra of lased enamels, phosphate bands ($600{\sim}500cm^{-1}$), B-carbonate bands (870, $1415{\sim}1455cm^{-1}$), and A-carbonate band ($1545cm^{-1}$) were observed. The amounts of phosphate bands and the B-carbonate bands were reduced, on the other hand, the amount of the A-carbonate band was increased by increase the energy density. 5. The SEM experiments reveal that the surface melting and recrystallization were appeared at $30J/cm^2$ and the cracks were observed at $70J/cm^2$. From above results, It may be suggested that the most effective energy density for improving acid resistance of tooth enamel with the irradiation of Nd-YAG laser was $50J/cm^2$. The mechanism of improving acid resistance were reduction of permeability due to surface melting and recrystallization of lased enamel and reduction of acid solubility of enamel due to decrease of carbonate content and growth of crystal.

• Journal of Life Science
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• v.20 no.1
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• pp.9-16
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• 2010

This study investigated cut-off values of body mass index (BMI) and body fat measures for metabolic syndrome (MS) in elderly Koreas. Questionnaire surveys, anthropometric measurements, medical examinations, and body composition analyses were conducted for 10,077 subjects aged 40-65 years in the health examinee cohort in Korea between 2004 and 2006. Cut-off values were identified using receiver-operating characteristic (ROC) curve analysis for both men and women. Stratified analyses by weight range (<60, 60-69, 70-79, and 80-89, ${\geq}90\;kg$ for men; <50, 50-59, 60-69, 70-79, ${\geq}80\;kg$ for women) were conducted. Among male subjects, the cut-off points were $25.5\;kg/m^2$ for BMI with a sensitivity of 70.0% and a specificity of 72.0%, and 26.1% for body fat percentage with a sensitivity of 60.6% and a specificity of 76.4%. Among female subjects, the cutoff points were $24.1\;kg/m^2$ for BMI with a sensitivity of 73.3% and a specificity of 68.8%, and 31.5% for body fat percentage with a sensitivity of 76.7% and a specificity of 65.6%. Stratified analysis by weight range showed that the cutoff points of BMI and body fat measures tended to higher as weight level increased. The results of our study suggest cut-off values of BMI and body fat measure for MS were similar to the general obesity criteria in Korea.

• Journal of Gastric Cancer
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• v.8 no.4
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• pp.217-224
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• 2008

Purpose: For most surgeons, colon interposition after gastrectomy remains an infrequently performed procedure because of its complexity. The aim of this study was to assess its technical feasibility and safety as a post-gastrectomy reconstruction method by reviewing our experience with colon interposition. Materials and Methods: From March 2001 to February 2002, 30 colon interpositions after-gastrectomy were done with using the ileo-ascending or transverse colon. We analyzed the clinicopathologic features and the surgical outcomes. Results: There were 16 males and 14 females in this study with a mean age of 67.5 years (range: 31 to 76 years). Twenty-five ascending colons and 5 transverse colons were used for the interposition, respectively. The mean operation time was 373 minutes (range: 204 to 600 minutes). There were 9 operative morbidities (30%) and 1 operative mortality. The restoration of bowel motility was noted at 3.8 postoperative days; a soft diet was started at 4.9 postoperative days and the duration of the hospital stay was 18.2 days. The percentage of weight loss in the patients with total, proximal and distal gastrectomy was 16.3%, 14.0% and 8.8%, respectively, at 6 months, and thereafter the weight loss gradually recovered as 8.1%, 7.5% and 5.6%, respectively, at 5 years postoperatively. Gastric stasis was the one of the most meaningful long-term complications, and especially in the patients who underwent distal gastrectomy with colon interposition. Conclusion: Colon interposition after gastrectomy was a very complex procedure with a long operating time and many anastomosis sites. The postoperative outcomes failed to achieve satisfactory weight gain and the patients displayed postprandial symptoms. This suggested that this procedure was not an appropriate procedure for conventional reconstruction after gastrectomy.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.3
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• pp.46-55
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• 2016

This work proposes a 13b 100MS/s 45nm CMOS ADC with a high dynamic performance for IF-domain high-speed signal processing systems based on a four-step pipeline architecture to optimize operating specifications. The SHA employs a wideband high-speed sampling network properly to process high-frequency input signals exceeding a sampling frequency. The SHA and MDACs adopt a two-stage amplifier with a gain-boosting technique to obtain the required high DC gain and the wide signal-swing range, while the amplifier and bias circuits use the same unit-size devices repeatedly to minimize device mismatch. Furthermore, a separate analog power supply voltage for on-chip current and voltage references minimizes performance degradation caused by the undesired noise and interference from adjacent functional blocks during high-speed operation. The proposed ADC occupies an active die area of $0.70mm^2$, based on various process-insensitive layout techniques to minimize the physical process imperfection effects. The prototype ADC in a 45nm CMOS demonstrates a measured DNL and INL within 0.77LSB and 1.57LSB, with a maximum SNDR and SFDR of 64.2dB and 78.4dB at 100MS/s, respectively. The ADC is implemented with long-channel devices rather than minimum channel-length devices available in this CMOS technology to process a wide input range of $2.0V_{PP}$ for the required system and to obtain a high dynamic performance at IF-domain input signal bands. The ADC consumes 425.0mW with a single analog voltage of 2.5V and two digital voltages of 2.5V and 1.1V.

• Journal of the Korean Orthopaedic Association
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• v.53 no.6
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• pp.513-521
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• 2018

Purpose: The purpose of this study was to assess the effectiveness and complications of an ultrasound-guided axillary brachial plexus block performed by orthopedic surgeons. Materials and Methods: From March to May 2017, an ultrasound-guided axillary brachial plexus block was performed on a total of 103 cases of surgery. A VF13-5 transducer from Siemens Acuson X300 was used. The surgical site was included in the range of the anatomic sensory distribution of the blocked nerve, except for the case where an operation time of more than 2 hours was expected due to multiple injuries and the operation of the upper arm. The procedure was performed by 2 orthopedic surgeons in the same method using 50 ml of solution (20 ml of lidocaine HCl in 2%, 20 ml of ropivacaine in 0.75%, 10 ml of normal saline in 0.9%). The success rate of anesthesia induction during surgery, anesthetic induction time, anatomical range of operation, duration of postoperative analgesia and complications were investigated. Results: The results from the 2 practices were similar. The anesthesia was successful in 100 out of 103 patients (97.1%). In these patients, the average needling time was 5.5 minutes (2.5-13.2 minutes), the average induction time to complete anesthesia was 18.4 minutes (5-40 minutes), and the average duration of postoperative analgesia was 402.8 minutes (141-540 minutes). The post-anesthesia immediate complications were dizziness in 1 case, nausea and vomiting in 4 cases, and peri-oral numbness in 2 cases, but surgery was performed without problems. All these 7 cases with complications recovered on the same day. A total of 3 cases failed with anesthesia, and they were treated by an injection with local anesthesia in the operation room in 2 cases and switched to general anesthesia in 1 case. Conclusion: An ultrasound-guided axillary brachial plexus block, which was performed by orthopedic surgeons allows anesthesia in a brief period and the high success rates of anesthesia for certain surgeries of the elbow and surgeries on forearm, wrist and hand. Therefore, it can reduce the waiting time to the operating room. This technique is a relatively safe procedure and dose selective anesthesia is possible.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.407-410
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• 2018

As the operating frequency of an electromagnetic wave increases, the maximum output and wavelength of the wave decreases, so that the size of the circuit cannot be reduced. As a result, the fabrication of a circuit with high power (of the order of or greater than kW range) and terahertz wave frequency band is limited, due to the problem of circuit size, to the order of ${\mu}m$ to mm. In order to overcome these limitations, we propose a source design technique for 0.1 THz~0.3 GW level with cylindrical shape (diameter ~2.4 cm). Modeling and computational simulations were performed to optimize the design of the high-power electromagnetic sources based on Cherenkov radiation generation technology using the principle of plasma wakefield acceleration with ponderomotive force and artificial dielectrics. An effective design guideline has been proposed to facilitate the fabrication of high-power terahertz wave vacuum devices of large diameter that are less restricted in circuit size through objective verification.