• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.71-79
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• 2016

Background: It is necessary to analyze radioactivity of naturally occurring radioactive materials (NORM) in products to ensure radiological safety required by Natural Radiation Safety Management Act. The pretreatments for the existing analysis methods require high technology and time. Such destructive pretreatments including grinding and dissolution of samples make impossible to reuse products. We developed a rapid and simple procedure of radioactivity analysis for thorium series in the products containing NORM. Materials and Methods: The developed method requires non-destructive or minimized pretreatment. Radioactivity of the product without pretreatment is initially measured using gamma spectroscopy and then the measured radioactivity is adjusted by considering material composition, mass density, and geometrical shape of the product. The radioactivity adjustment can be made using scaling factors, which is derived by radiation transport Monte Carlo simulation. Necklace, bracelet, male health care product, and tile for health mat were selected as representative products for this study. The products are commonly used by the public and directly contacted with human body and thus resulting in high radiation exposure to the user. Results and Discussion: The scaling factors were derived using MCNPX code and the values ranged from 0.31 to 0.47. If radioactivity of the products is measured without pretreatment, the thorium series may be overestimated by up to 2.8 times. If scaling factors are applied, the difference in radioactivity estimates are reduced to 3-24%. Conclusion : The developed procedure in this study can be used for other products with various materials and shapes and thus ensuring radiological safety.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.784-795
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• 2007

In this thesis, the Multi element antenna with wideband and enhanced gain characteristic is proposed to operate at both frequency range from 824 MHz to 896 11Hz for the CDMA and frequency range from 908.5 MHz to 914 MHz for the RFID band. The proposed antenna has tile size of $35{\times}15{\times}5mm^3$ in order to put it in the A model of S company and each element of the proposed antenna is folded to obtain the minimum size. To obtain the antenna with wideband and high gain characteristic, the radiator of the antenna is divided into 4 elements. As a result, bandwidth of the proposed antenna become broader and lower center frequency is appeared due to increased and lengthened current path. Moreover, the enhanced gain characteristic is verified because divided element structure that induct uniform current distribution can get increased antenna efficiency. To attain more uniform current distribution, modified structure of the feeding point that can deliver currents directly is designed. The antenna that alters the feeding structure has higher gain value. Each element is folded to increase the current paths considering the current directions to attain the miniaturization of the antenna. To measure the handset antenna, the handset case must be considered. Even though antenna is designed for predicted characteristic, the resonance frequency is shifted and antenna gain is deteriorated at predicted frequency while antenna is set in the handset case. 1.08 GHz of the resonant frequency is determined after frequency shift from 150 MHz to 200 MHz is confirmed and the maximum gain is measured as 3.1 dBi while antenna is not set in the handset. In case handset case is considered, the experimental results show that the impedance bandwidth for VSWR<2 is from 0.824 GHz to 0.936 GHz(110 MHz). This result appears that the proposed antenna can cover both CDMA and RFID band at once. The measured gain is from -3.4 dBi to -0.5 dBi and it has omni-directional pattern practically.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.4
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• pp.204-212
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• 2005

Recognition has emerged that nutrient inputs from the submarine discharge of fresh, brackish, and marine groundwaters into the coastal ocean are comparable to the inputs via river discharge. The coastal areas of the Korea peninsula and adjacent seas exhibit particular importance in the role of submarine groundwater discharge (SGD), in terms of the magnitude of SGD and associated continental material fluxes. For example, in the southern sea of Korea, SGD transports excess nutrients into the coastal regions and thus appears to influence ecosystem changes such as the outbreak of red tides. Around volcanic island, Jeju, which is composed of high permeability rocks, the amount of SGD is higher by orders of magnitude relative to the eastern coast of North America where extensive SGD studies have been conducted. In particular, nutrient discharge through SGD exerts a significant control on coastal ecosystem changes and results in benthic eutrophication in semi-enclosed Bang-du bay, Jeju. In the entire area of the Yellow Sea, tile submarine discharge of brackish groundwater and associated nutrients are found to rival the river discharges into the Yellow Sea, including those through Yangtze River, Han River, etc. In the eastern coast of the Korea peninsula, SGD is significantly higher during summer than winter due to high hydraulic gradients and due to wide distribution of high permeability sandy zones, faults, and fractures. On the other hand, in the estuarine water, downstream construction of the dam in the Nakdong River, SGD was highest when the river discharge was lowest (but water level of the dam was highest). This suggests that even though there is no visible freshwater discharge into this estuary, the discharge of chemical species is significant through SGD. On the basis of the results obtained from the coastal areas of the Korea peninsula, SGD is considered to be an important pathway of continental contaminants influencing tidal-flat ecosystems, red tides, and coral ecology. Thus, future costal management should pay great attention to the impact of SGD on coastal pollution and eutrophication.

• Korean Journal of Poultry Science
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• v.6 no.1
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• pp.12-23
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• 1979

This experiment was carrid out to investigate the interaction between boilelr strains and nutrition levels, and the performances of four broiler strains such as Han Hyup 603, Hubbard, Anak and Filch when they were fed by four different nutrition levels (High Protein and energy; HP. HE., Medium Protein and energy; MP. ME., Low Protein ana energy; LP. LE., and low protein and energy; LLP. LLE.). The data used in this study were obtained from a total of 1200 broiler type chicks in Poultry Testing Station, Korean Poultry Association from June 16, to August 11, 1978. Differences of all characters among four nutrition levels were significant except viability and carcass rate. HP. HE and MP. ME treatments showed nearly the same performances in body weight, feed efficiency and point, spread but they were significantly superior to those of LP. LE and LLP. LLE. There were not significant differences among four strains in feed efficiency and viability but other characters, body weight, point spread and carcass rate were observed that the performance of the best strain B was significantly superior to strain D but it was not recognized significance compared with strain A, C in tile result of statisticel analysis. In the interaction between strains and nutrition levels, body weight at high and levels showed significantly differences but at low and low nutrition levels were nearly same among four strains. Therefore this study demonstrated that comparision of body weights between strains should be performed at medium nutrition level or above. Also point spread calculated as index of body weight and feed efficiency was observed that strain B at low nutrition level is excellently higher than other strains and there were little differences at low nutrition level among all strains. It was found that ]it tie differences between performances of high arid medium levels seemed to be as the reason of high fat addition for energy source to high mutrition feed, and in general superior strain showed good performance at all the nutrition levels in$.$all characters but in body weight and point spread there were significantly different responses with different nutrition level, The most superior strain B among four strains earned the most profit per bird, Although performances of high and medium nutrition levels were nearly the same, medium nutrition level also showed the most profit because the feed cost of high nutrition level was higher than that of medium nutrition level.

• Journal of the Korean Arthroscopy Society
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• v.9 no.2
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• pp.222-231
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• 2005

Purpose: This article describes a double-bundle ACL reconstruction technique using a five-strand hamstring tendon autograft with conventional anteromedial bundle reconstruction and additional posterolateral bundle reconstruction. Operative technique: For the tibial tunnel, the conventional single tunnel technique is performed and for the femoral tunnel, the double tunnel technique is performed with the anteromedial and posterolateral bundle. After minimal notchplasty, the anteromedial femoral tunnel is prepared with leaving one milimeter of posterior femoral cortex within the over-the-top, which if positioned at the 11-o'clock orientation for the right knee or at the 1-o'clock position for the left knee. The posterolateral femoral tunnel that is located 5 to 7 mm superior to the inner margin of the lateral meniscus anterior horn at $90^{\circ}$ of flexion is prepared with tile outside-in technique using a 4.5 cannulated reamer. The graft material for the double bundle reconstruction is made of the conventional four-strand hamstring autograft in the anteromedial bundle and of a single-strand semitendinosus tendon in the posterolateral bundle. The anteromedial bundle is fixed with using a rigid fix system on the femoral side and the posterolateral bundle is fixed to tie with the miniplate from the outside femur. Then, with the knee in $10^{\circ}\;to\;20^{\circ}$ of flexion, a bioabsorbable screw is simultaneously applied to achieve tibial fixation with tensioning of both bundles. Conclusion: A double bundle reconstruction with five-strand hamstring autograft, which is designed with a favorable conventional anteromedial bundle and an additional posterolateral bundle to restore rotation stability, seems to be a very effective method for the treatment for ACL instabilities.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.100-109
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• 2006

This study evaluated the effects of water velocity, substrates, and phosphorus concentrations on the growth of filamentous periphytic algae (FPA) in the two types of artificial channel systems using treated wastewater. Controlled parameters included 5 ${\sim}$ 15 cm $s^{-1}$ for the water velocity; 10 and 20 mm wire meshes, natural fiber net, gravel and tile for the substrates: and 0.05 ${\sim}$ 1.0 mgP $L^{-1}$ for the P concentration. Algal growth rate of FPA was compared using both chi. a and dry weight change with time. Under the controlled water velocity range, the growth of FPA increased with the velocity, but the maximum growth rate was shown in the velocity of 10 cm $s^{-1}$. The substrate that showed the maximum growth of FPA differed between the artificial channel and indoor channel, due to the influence of suspended matters which caused the clogging of the meshed substrates. Under the controled range of P concentration, the growth rates of all three FPA species (Spirogyra turfosa, Oedogonium fovelatum, Rhizoclonium riparium) increased with the P increase, but they showed the differential growth rates among different P concentrations. The results of this study suggest that under the circumstance having an large amount of nutrients FPA develop the biomass rapidly and that even a little increase over the threshold velocity causes the detachment of filamentous periphytic algae. Thus, FPA dynamics in eutrophic streams, such as those receiving treated wastewater, seem to be sensitive to the water velocity. On the other hand, detached algal filaments could deteriorate water quality and ecosystem function in receiving streams or down-stream, and thus they need to be recognized as an important factor in water quality management in eutrophic streams.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.155-168
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• 1986

In Korea, lots of Israeli carp (Cyprinus carpio) are cultured by means of net cages in dams and lakes, but many carp have been subjected to heavy infestation of the cestoid, Bothriocephalus opsariichthydis. Nevertheless the parasitic state and life history of the cestoid are not yet reported. This reason led the author to study the parasitic state and life history of B. opsariichthydis parasitized in the carp in order to take effective control measures against its damage. Israeli carp were sampled from two fish farms, in Taech'on and Kyongch'on. After dissection of the specimens, the cestoid were obtained and the parasitic rates were examined. After taking the eggs from adult worms, the development of the eggs were observed. Coracidia were exposed to four kinds of crustaceans in order to investigate the infection rate and development of the larva. Finally, tile development of the larva in the final host was investigated. The fully mature eggs were in the cleavage stage, when they are released, and the size ranged 47.5 to 55.0 $(50.9){\times}30.0$ to 32.5 (31.1) um, in the state of under-developed coracidia and blastomeres. The parasitic rate of the cestoid in Israeli carp from Taechon was $55.5\%$ in 1984 and $21.6\%$ in 1985, that from Kyongchon was $64.7\%$ in 1984, and color carp from Kusan was $14.9\%$ in 1984. The eggs were hatched to coracidia within 48 hours under 26 to $28^{\circ}C$. The cestoid showed a strong affinity to Thermocyclops hyalinus and Paracyclops fimbriatus and the infection rates were $93.5\%$ and $75.5\%$, respectively. At 14 days after the infection to Thermocyclops hyalinus and Paracyclops fimbriatus, the larvae of the cestoid grew into fully developed procercoids; 207 to $226 (214){\times}90$ to 102 (94) um in size. Sixty days after carp have ingested the Thermocyclops hyalinus infected with the fully developed procercoids, the larvae of the cestoid matured into adult worms in the intestines of the carp.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.164-175
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• 2001

Purpose : Alport syndrome is a hereditary nephrotic disease characterized by progressive nephrotic symptom, sensorineural hearing loss, ophthalmic abnormality, typical microscopic findings, and familial occurrence. In this study, we tried to find the risk factors related with its prognosis by taking a close observation on clinical symptoms of children with Alport syndrome reviewing retrospectively. Materials & methods : We chose children diagnosed as Alport syndrome in renal biopsy during 20 years(from 1980, Jan. until 1999, Dec.) who could receive follow up studies in tile department of pediatrics. They were divided into two groups by comparing renal function at the time of diagnosis and at current status. We compared several clinical aspects in them, and applied nonparametric test for statistical analysis. Results : The sex ratio(male:female) of 24 children was 3:1. The most common clinical symptom presented at their first visit was gross hematuria. Among those 24 children, 11 cases($46\%$) of progressing into chronic renal failure(Group II) were observed. Hypertension, proteinuria and edema were seen much frequently in group II. The level of serum protein, albumin, and creatinine clearance were decreased while BUN, creatinine were relatively increased. All the results were statistically significant. Conclusion Clinically significant risk factors related to prognosis in Alport syndrome were the presence of hypertension, edema, and proteinuria at the time of diagnosis. Also, the level of serum protein, albumin, BUN, creatinine, and glomerular filtration rate were proved to be important factors in predicting prognosis. We believe that studies on these possible risk factors would be of great help in treating and predicting prognosis of children suffering with Alport syndrome. (J Korean Soc Pediatr Nephrol 2001;5 : 164-75)

• Childhood Kidney Diseases
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• v.6 no.1
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• pp.37-47
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• 2002

Purpose: We reviewed the clinical manifestations, responsiveness to treatment, and prognosis in children with nephrotic syndrome. Methods: Medical records of 159 children with idiopathic nephrotic syndrome who were admitted to the pediatric department of Chonbuk National University Hospital from January 1979 to December 2000 w ere retrospectively reviewed. Results: There were 32 females and 127 males. The most common age group was between 3 and 5 years of age among the 159 children with nephrotic syndrome. Generalized edema ($75.5\%$), scrotal edema ($20.1\%$), upper respiratory infection ($19.5\%$), and ascites ($28.3\%$) were frequently observed. After the initial steroid therapy, diuresis occurred within tile first two weeks in 138 children, and proteinuria disappeared within the first two weeks in 105 children. Among 159 patients who received initial daily steroid therapy, 110 children were in complete remission, 29 children were in partial remission and 20 children were in poor response state. Hematuria, hypertension and elevated serum creatinine were more frequently observed in the partial and the poor response groups than in the complete remission group. Among 107 children who were followed up for more than one year, 78 children were in complete remission and 55 children were relapsed within the first one year after steroid therapy. Renal biopsy was undertaken in 76 children and 53 children had minimal change nephrotic syndronm. Conclusion: Our study showed that illost children with idiopathic nephrotic syndrome have a good responsiveness to steroid therapy and even most children show frequent relapse during 1st year after remission, long term prognosis is excellent.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.100-108
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• 2001

Purpose : We investigated the incidence and predisposing factors of pulmonary embolism in minimal change nephrotic syndrome(MCNS). Methods : Lung perfusion scan using 99mTC-MAA were done on 14 patients who were diagnosed to minimal change nephrotic syndrome. Group h: Five patients who had perfusion defects on scan, Group B; Nine patients who had no perfusion defect on scan. Between the two groups, the differences of platelet number, hematocrits, albumin, cholesterol, triglyceride, proteinuria were evaluated. Results : Five patients were found to have perfusion defect consistent with pulmonary embolism($35.7\%$). However, there were minimal or no respiratory symptoms and signs. In our laboratory studies, the mean proteinuria on admissions was $676{\pm}31\;mg/m2/hr$ in the group with pulmonary embolism, and $313{\pm}28\;mg/m2/hr$ in the group without pulmonary embolism. There were more severe proteinuria in group with pulmonary embolism(P<0.05). The mean platelet count at early stage of remission after steroid treatment was $746,600{\pm}280,000/mm3$ in the group with pulmonary embolism, $511,890{\pm}90,000/mm3$ in the group without pulmonary embolism. There were significant difference of platelet count between the two groups(P<0.01). In patients with pulmonary embolism, there were more higher and sustained increasement of platelet count. All cases of pulmonary embolism were treated with dipyridamole(5 mg/kg). In 4 cases the perfusion defects were improved in two weeks, however, one case showed persistent perfusion defect after 1 month. Conclusion : Our study suggested that pulmonry embolism might be one of tile major complications in childhood MCNS The occurrence rate was correlated with severity of proteinuria before treatment and sustained increasement of platelet counts in early remission state after steroid treatment. Therefore, the scintigraphic pulmonary perfusion study is mandatory in childhood MCNS, especially in the high risk patients, such as the patients with severe proteinuria and sustained increasement of platelet count. (J Korean Soc Pediatr Nephrol 2001;5 : 100-8)