• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.1
• /
• pp.1-14
• /
• 2006

Tropospheric aerosols are highly variant in time and space due to non-uniform source distribution and strong influence of meteorological conditions. Backscatter lidar measurement is useful to understand vertical distribution of aerosol. However, the backscatter lidar equation is undetermined due to its dependence on the two unknowns, extinction and backscattering coefficient. This dependence necessitates the exact value of the ratio between two parameters, that is, the lidar ratio. Also, Iidar ratio itself is useful optical parameter to understand properties of aerosols. Tropospheric aerosols were observed to understand variance of lidar ratio at Anmyeon island ($36.32^{/circ}N$, $126.19^{/circ}E$), Korea using a multi-wavelength raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea during measurement periods; March 15$\sim$April $16^{th}$, 2004 and May 24$\sim$ $8^{th}$ 2005. Extinction coefficient, backscattering coefficient, and lidar ratio were measured at 355 and 532 nm by the Raman method. Different types of aerosol layers were distinguished by the differences in the optical properties such as Angstrom exponent, and lidar ratio. The average value of lidar ratio during two observation periods was found to be $50.85\pm4.88$ sr at 355 nm and $52.43\pm15.15$ sr at 532 nm at 2004 and $57.94\pm10.29$ sr at 355 nm and $82.24\pm15.90$ sr at 532 nm at 2005. We conduct hysplit back-trajectory to know the pathway of airmass during the observation periods. We also calculate lidar ratio of different type of aerosol, urban, maritime, dust, continental aerosols using OPAC (Optical Properties of Aerosols and Clouds), Remote sensing of atmospheric aerosol using a multi-wavelengh lidar system with Raman channels is quite and powerful tool to characterize the optical propertises of troposheric aerosols.

• The Journal of the Petrological Society of Korea
• /
• v.11 no.2
• /
• pp.90-102
• /
• 2002

The studied Fe-REE ore consists of magnetite, ankerite, siderite, magnesite and strontianite as the major constituent, and monazite, columbite, fergusonite, apatite, aegirine-augite, Na-amphibole, pyrite, chalcopyrite, sphalerite, molybdenite and barite as accessaries. Wall rock of ore deposits is replaced to fenite due to Na-metasomatism and mainly consists of sugary albite and Na-amphibole. Monazite $Ce_{0.49}La_{0.31}Pr_{0.14}Nd_{0.03}Gd_{0.03})PO_4$ is the main mineral for REE deposit and shows myrmekitic intergrowth with strontianite $Ca_{0.02-0.16}Sr_{0.84-0.98}CO_3$ and is corroded by carbonate minerals. Mineral forming sequence can be divided into early and late periods by the development of microfractures. The early period minerals such as magnetite, ankerite, magnesite, monazite and apatite show well developed networks of microfractures due to cataclastic deformation caused by enriched $CO_2$ gas in melts during emplacement. The late minerals of columbite, fergusonite, siderite molybdenite, chalcopyrite and sphalerite formed after the brecciation event and have little micro-fractures. Ankerite, magnesite, monazite, strontianite, barite and pyrite seem to be formed continuously from the ealy to the late period since they show textures both with well developed fractures and also with little fractures. Mineral chemistry, mineral assemblages such as various carbonate minerals, magnetite, REE minerals of monazite and fergusonite, Sr mineral of strontianite, and Nb minerals of columbite, myrmekitic texture of monazite and ankerite, and well developed fenite along ore deposits observed from this studied area strongly indicate that this Hongcheon Fe-REE ore deposits are formed from carbonatitic melt and its rock type is late differentiated Fe-carbonatite or ankerite-carbonatite.

• Journal of Radiation Protection and Research
• /
• v.20 no.4
• /
• pp.265-274
• /
• 1995

Diffusivity of ions of radioactive species is an important factor for designing radwaste repositories. Clay minerals are used as a backfill material. In this study, diffusion of Co-60 ions through the bentonite having various densities has been studied, using a diffusion cell. The measured diffusivities of Co-60 ions decreased as the density of bentonite increased. The diffusivity of Co-60 ion decreased from $8.79{\times}10^{11}m^2/s$ to $6.82{\times}10-13m^2/s$ as the clay dry bulk density increased from 0.41 to 2.03g/cm3. The diffusivity of Co ion was larger than that of Sr ion at low density, but the diffusivity of Co ion decreased rapidly as the density of clay increased and became smaller than that of Cs ion at high density. This phenomenon is thought to be caused by the rapid decrease of the fraction of mobile cation since the chemical combination of Co ions with oxygen or oxide on clay surface and the entrance of Co ions into the crystal structure of clay increase as the clay density increases. This change should be considered especially in designing the clay back fill for low and intermediate radwaste disposal facilities.

• Journal of Radiation Protection and Research
• /
• v.29 no.2
• /
• pp.73-90
• /
• 2004

The Reg. Guide 1.109 model was reviewed against its applicability to calculating radionuclide concentrations in agricultural products for operating nuclear facilities and an improved method was proposed. The model was so modified that the radionuclides deposited since the start of operation could be considered in assessing the root uptake. Translocation factors were introduced in the equation for calculating the concentrations in edible parts due to direct plant deposition. Values specific to Korea were set up for the input parameters of the modified model. The concentrations of $^{54}Mn,\;^{60}Co,\;^{90}Sr\;and\;^{137}Cs$ in rice seeds, Chinese cabbage and radish root were calculated for various hypothetical deposition histories using the Reg. Guide 1.109 model and the modified model with parameter values in the guide and those specific to Korea put in alternately. Through comparisons among the results, it could be expected that the use of the modified model with the input of parameter values specific to Korea would result In a more resonable and realistic assessment.

• Journal of Animal Environmental Science
• /
• v.20 no.4
• /
• pp.173-176
• /
• 2014

This study was conducted to investigate the effect of weaning period on the vocalization frequency of Hanwoo calf. Twelve Hanwoo calves were allocated into 4 groups, control (forced weaning on 90days) and treatment (weaning on 70, 90 and 120days with 5 adaptation days). After weaning, behavior and vocalization of Hanwoo calves were recorded on 3 consecutive days with closed circuit television (DTC-R5254, Digite Co., Ltd., Korea) and digital audio tape recorder (SR-900, Idamtech Co., Ltd., Korea). Vocalization frequency of Hanwoo calf were not significance difference with control and treatment group. Thus, additional studies of feed intake and body weight gain were needed to determine the weaning period of Hanwoo calves.

• Tuberculosis and Respiratory Diseases
• /
• v.66 no.2
• /
• pp.93-97
• /
• 2009

Background: Belotecan (Camtobell, CKD-602, Chongkundang Pharm., Korea), a camptothecin derivative, has anticancer effects by inhibiting topoisomerase I such as topotecan. This study observed the response, survival and toxicity of belotecan monotherapy after the failure of etoposide and platinum (EP). Methods: Forty nine small cell lung cancer (SCLC) patients (M/F=41/8; age, 64.5${\pm}$7.6 (mean${\pm}$SD) years), who failed in their first line chemotherapy were enrolled in this study. Twenty one SCLC patients showed relapsed lung cancer more than 90 days after their priorEP chemotherapy (sensitive relapse group, SR) and 28 patients relapsed within 90 days (refractory relapse group, RR). Results: The response rate was 25%. Eleven patients showed partial responses and 5 patients could not be checked. The response rate of the SR and RR patients was similar. The relative dose intensity was lower in the responders (78${\pm}$15%) than non-responders (83${\pm}$13%, p=0.03). The median survival time (MST) was 10.3 months (290 days). The MST of the non-responders and responders was 186 days (95% CI; 67-305) and 401 days (95% CI; 234-568, p=0.07), respectively. The median progression free survival (MPFS) was similar in the SR (79 days) and RR (67 days) patients. Grade 3-4 neutropenia, anemia, and thrombocytopenia were observed in 59.6%, 12.8% and 23.4% of patients, respectively. Conclusion: The efficacy and survival were demonstrated in the second-line setting. However, a randomized comparative trial with topotecan will be needed.

• The Korean Journal of Nuclear Medicine
• /
• v.38 no.6
• /
• pp.516-521
• /
• 2004

Background: Radioactive iodine (RAI) therapy and whole-body scanning are the fundamentals of treatment and follow-up of patients with differentiated thyroid cancer. It is generally accepted that a Thyroid-Stimulating Hormone (TSH) level of at least 30 ${\mu}U/ml$ is a prerequisite for the effective use of RAI, and that it requires 4-6 weeks of off-thyroxine to attain these levels. Because thyroxine withdrawal and the consequent hypothyroidism are often poorly tolerated, and occasionally might be hazardous, it is important to be certain that these assumptions are correct. We have measured serial changes in serum TSH after total thyroidectomy or withdrawl of thyroxine in patients with thyroid cancer. Subjects and Methods: Serum TSH levels were measured weekly after thyroidectomy in 10 patients (group A) and after the discontinuation of thyroxine in 12 patients (group B). Symptoms and signs of hypothyroidism were also evaluated weekly by modified Billewicz diagnostic index. Results: By the second week, 78% of group A patients and 17% of group B patients had serum TSH levels ${\geq}30{\mu}U/ml$. By the third week, 89% of group A patients and 90% of group B patients had serum TSH levels ${\geq}30{\mu}U/ml$. By the fourth week, all patients in two groups achieved target TSH levels and there were no overt hypothyroidism. Conclusion: in all patients, serum TSH elevated to the target concentration (${\geq}30{\mu}U/ml$) within 4 weeks without significant manifestation of hypothyroidism. The schedule of RAI administration could be adjusted to fit the needs and circumstances of individual patients with a shorter preparation period than the conventional.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2117-2120
• /
• 2004

본 논문은 UV-LIGA 공정, 후막공정을 이용한 바이오센서용 magnetic bead 분리 장치의 제작 기술개발에 관한 것이다. 최근 MEMS(microelectromechanical system) 기술을 이용한 바이오센서에 대한 연구가 활발하게 이루어지고 있다. 이러한 바이오센서 분야 중 혈액이나 다른 원하지 않는 물질을 분리해 주는 분리장치는 MEMS 기술을 이용해 구현이 매우 어려운 부분 중에 하나이다. 기존의 UV-LIGA 공정과 도금법을 이용한 마이크로 전자석 제작하여 분리장치를 제작하는 경우 제작 공정이 매우 복잡하며 매우 많은 공정비용을 요구한다. 이러한 단점을 해결하기 위해 본 논문에서는 Sr 계연의 고분자 자석과 3차원 PDMS(poly-dimethylsiloxane) 마이크로 채널 공정을 이용해 분리장치를 제작하였다. 제작된 분리장치는 $0{\sim}30{\mu}{\ell}$/min 의 속도에서 유체를 흘렸을 90% 이상의 분리 효율을 나타냈다. 개발된 분리 장치는 연재질의 PDMS 로 제작되어 일회용 바이오센서에 적용이 가능하다.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1621-1623
• /
• 2004

The $Pb(Zr_{0.52}Ti_{0.48})O_3/(Ba_{0.6}Sr_{0.4})TiO_3$ [PZT(52/48)/BST(60/40)] heterolayered thin films were deposited on Pt/Ti/$SiO_2$/Si substrates by using the RF sputtering method with RF powers of 60,70,80,90[W]. All thin films showed the peaks of the tetragonal phase. Increasing the RF power, dielectric constant and loss of the PZT(52/48)/BST(60/40)] heterolayered thin films were decreased. The thickness ratio of PZT and BST thin films was 1/1. The relative dielectric constant and the dielectric loss of the PZT(52/48)/ BST(60/40) heterolayered thin films were 562 and 13%, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.10
• /
• pp.505-509
• /
• 2004

The (Sr/sub 0.9/Ca/sub 0.1/)TiO₃(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/SiO₂/Si) using RF sputtering method at various substrate temperature. The optimum conditions of RF power and Ar/O₂ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin film was about 18.75[Å/min]. The crystallinity of SCT thin films were increased with increase of substrate temperature in the temperature range of 100～500[℃]. The dielectric constant of SCT thin films were increased with the increase of substrate temperature, and changed almost linearly in temperature ranges of -80～+90[℃]. The current-voltage characteristics of SCT thin films showed the increasing leakage current as the substrate temperature increases.