• Progress in Medical Physics
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• v.8 no.2
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• pp.87-102
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• 1997

The absolute absorbed dose can be determined according to the measurement conditions; measurement material, detector, energy and calibration protocols. The purpose of this study is to compare the absolute absorbed dose due to the differences of measurement condition and calibration protocols for photon beams. Dosimetric measurements were performed with a farmer type PTW and NEL ionization chambers in water, solid water, and polystyrene phantoms using 6MV photon beams from Siemens linear accelerator. Measurements were made along the central axis of 10cm $\times$ 10cm field size for constant target to surface distance of 100cm for water, solid water and polystyrene phantom. Theoretical absorbed dose intercomparisons between TG21 and IAEA protocol were performed for various measurement combinations of phantom, ion chamber, and electrometer. There were no significant differences of absorbed dose value between TG21 and IAEA protocol. The differences between two protocols are within 1％ while the average value of IAEA protocol was 0.5％ smaller than TG21 protocol. For the purpose of comparison, all the relative absorbed dose were nomalized to NEL ion chamber with Keithley electrometer and water phantom, The average differences are within 1％, but individual discrepancies are in the range of - 2.5％ to 1.2％ depending upon the choice of measurement combination. The largest discrepancy of - 2.5％ was observed when NEL ion chamber with Keithley electrometer is used in solid water phantom. The main cause for this discrepancy is due to the use of same parameters of stopping power, absorption coeficient, etc. as used in water phantom. It should be mentioned that the solid water phantom is not recommended for absolute dose calibration as the alternative of water, since absorbed dose show some dependency on phantom material other than water. In conclusion, the trend of variation was not much dependent on calibration protocol. However, it shows that absorbed dose could be affected by phantom material other than water.

• The Journal of the Petrological Society of Korea
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• v.21 no.1
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• pp.1-12
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• 2012

The Baegdusan volcano is one of the most active volcanoes in northeastern Asia, and the 10th century eruption was the most voluminous eruption in the world in recent 2,000 years. During the period from 2002 to 2005, volcanic earthquakes and abnormal surface distortions by suspected subsurface magma intrusion beneath the volcano were observed in the Baegdusan area. Seismic activity has gradually increased with earthquake swarms during 2002-2003 and hundreds of seismic event in a day, especially annual peak of 2,100 in 2003. Then the number of seismic activity has declined since 2006 to the background level in 1999-2001. According to the typical frequency of volcanic earthquakes in the Baegdusan volcano, the frequency distribution of typical volcanic earthquakes between 2002 and 2005 indicates that all the main frequency of the earthquakes basically falls down less than 5 Hz and 5-10 Hz. These events are all the VT-B and LP events caused by the shallow localized fracture and intrusion of magma. The horizontal displacement measurement by GPS during the period from 2000 to 2007 of the Baegdusan stratovolcano area indicates that an inflated process has been centered at the summit caldera since 2002. The displacement between 2002 and 2003 reached at a maximum value of 4 cm. After 2003, the deformation rate of the volcano continued to decrease with unusual variation during the period from 2006 to 2007. After 2003 the vertical displacement uplift rate falls down gradually but still keeps in an uplift trend in northern slope. It is generally believed that when $^3He/^4He(R)$ in a gas sample from a hot spring exceeds $^3He/^4He(R)$ in the atmosphere, it can be concluded that mantle-source. And temperatures of hot springs are rising steadily to $83^{\circ}C$. It is unrest signals at the Baegdusan, which is potentially active. The Baegdusan volcano is now in unrest status, there is eruption threat in the near future. Intensified monitoring and emergency response plan for volcanic risk mitigation are urgent for the volcano.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.301-308
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• 1982

Chungkook-jang Koji was fermented with rice straw at $40^{\circ}C\;and\;50^{\circ}C$ for 72 hours. The changes of proximate composition, pH, titrable acidity, nitrogen compounds, protease activity and free-amino acids during the fermentation were investigated. Moisture, lipid and protein contents remained essentially unchanged during the fermentation. The pH was gradually increased from 6.4 to 7.46 and 7.82 at $40^{\circ}C\;and\;50^{\circ}C$, respectively, after 72 hour fermentation. Amino type and water soluble nitrogen increased as fermentation progressed. however, the former slightly decreased after 60 hour fermentation. Chungkook-jang fermented at $40^{\circ}C$ showed somewhat higher protease activity than $50^{\circ}C$. However, protease activity at both fermentation temperatures showed the same trend; that is, it increased until 48 hour fermentation and thereafter decrease. Free amino acid content of Chung-kook-jang after 72 hour fermentation at $40^{\circ}C$ was 6 times greater than that of the steamed soybean, while it was 2.5 times greater at $50^{\circ}C$. Based on these results. it seems that the optimum fermentation conditions for Chungkook-jang were $40^{\circ}C$ and 72 hours.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.2
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• pp.105-118
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• 2000

Anchored measurements (12.5 hr) of suspended sediment concentration and other hydrodynamic parameters were carried out at two stations located at the entrance to Hampyung Bay in summer (August 1999). Tidal variations in water temperature and salinity were in the range of 26.0-27.9$^{\circ}C$ and 30.9-31.5, respectively, indicating exchange offshore and offshore water mass. Active tidal mixing processes at the entrance appear to destroy the otherwise vertical stratification in temperature and salinity in spite of strong solar heating in summer. On the contrary, suspended sediment concentrations show a marked stratification with increasing concentrations toward bottom layer. Clastic particles in suspended sediments consist mostly of very fine to fine silt (4-16 ${\mu}$m) with a poorly-sorted value of 14.7-25.9 ${\mu}$m. However, at slack time with less turbulent energy, flocs larger than 40 ${\mu}$m are formed by cohesion and inter-collision of particles, resulting in a higher settling velocity. Strong ebb-dominated and weak flood dominated tidal currents, in the southwestern and the northeastern part, respectively, result in a seaward residual flow of -10${\sim}$-20 cm $s^{-1}$ at station H1 and a bayward residual flow less than 5.0 cm $s^{-1}$ at station H2. However, mean concentration of suspended sediments at station H1 is higher at flood (95.0-144.1 mg $1^{-1}$) than in ebb (75.8-120.9 mg $1^{-1}$). On the contrary, at the station H2, the trend is reversed with higher concentration at the ebb (84.7-158.4 mg $1^{-1}$) than that at the flood (53.0-107.9 mg $1^{-1}$). As a result, seaward net suspended sediment fluxes ($f_{s}$) are calculated to be -1.7 ${\sim}$-$15.610^{3}$ kg $m^{-2}$ $s^{-1}$ through the whole water column. However, the stations H1 and H2 show definitely different values of the flux with higher ones in the former than in the latter. Alternatively, depth-integrated net suspended sediment loads ($\c{Q}_{s}$) for one tidal cycle are also toward the offshore with ranges of 0.37${\times}$$10^{3}$ kg $m^{-1}$ and 0.21${\times}$$10^{3}$ kg $m^{-1}$, at station H1 and H2, respectively. This seaward transport of suspended sediment in summer suggests that summer-time erosion in the Hampyung muddy tidal flats is a rather exceptional phenomenon compared to the general deposition reported for many other tidal flats on the west coast of Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.353-359
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• 2012

The identification of effective root zone would clarify dynamics of plant available water and soil water balance. Using the relationship between soil properties and electrical resistivity (ER) the purpose of this research is to identify soil zone affected by a plant root activity using electrical resistivity tomography (ERT) technique. Four plastic containers were prepared for two different soil textures (clay and sandy loam) and one container for each texture was selected for planting four corn seedlings (Zea mays L.) and the others were prepared for the blank. For ERT monitoring, we prepared 0.8 m plastic sticks with 17 electrodes installed with 5 cm space. The Ministing (AGI Inc., Texas) instrument for electrical resistivity measurement and semi-auto converter of electrode arrangement were set up for dipole-dipole array. During 2 months of the corns growing, ERT monitoring was made 3 to 4 days after the irrigation practice. Despite of the same amount water supplied into soils, two textures showed very different apparent resistivity values due to different clay content. The apparent electrical resistivity is consistently lower in clay loam comparing to sandy loam soil implying that plant root does not significantly alter the overall trend of resistivity. When plant root system, however, is active both soils with plants showed 2-7 times higher electrical resistivity and higher coefficient variation than soils without plant, implying the effect of root system on the resistivity, in which may caused by. This result suggests plant root activities regulating the soil water dynamics mainly control the variation of electrical resistivity over soil textural difference. Therefore the identification of water uptake zone would highly be correlated to plant root activities, thus ERT will be feasible approach to identify spatial characteristics of a plant root activity.

• Journal of the Korean Magnetic Resonance Society
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• v.4 no.1
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• pp.19-28
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• 2000

Authors evaluated alterations of observable metabolite ratios between the cerebral lesion and the contralateral region related to the clinical symptomatic side in levodopa-treated Parkinson's disease (PD) and investigated correlation between age in patients with PD and metabolite ratios of the lesion. Patients with levodopa-treated PD (n = 54) and age-matched normal controls (n = 15) underwent magnetic resonance spectroscopy (MRS) examinations using a stimulated echo acquisition mode (STEAM) pulse sequence that provided 2$\times$2$\times$2 cm3 volume of interest in the selected regions of substantia nigra (SN) and putamed-globus pallidus (PG). To evaluate dependence of metabolite ratios on age, we divided into two groups (i.e., younger and older age). We quantitatively measured N-acetylaspartate (NAA), creatine (Cr), choline-containing compounds (Cho), inositols (Ins), and the sum of glutamate (Glx) and GABA levels and obtained proton metabolite ratios relative to Cr using a Marquart algorithm. Compared with the contralateral region, a significant neuronal laterality of the NAA/Cr ratio in the lesion of SN related to the clinical symptomatic side was established (P = 0.01), but was not established in the lesion of PG (P = 0.24). Also, Cho/Cr ratio tended toward significance in the lesion of SN (P = 0.07) and was statistically significant in the lesion of PG(P = 0.01). Compared with that in the younger age group, NAA/Cr ratio in the older age was decreased in the lesion of SN (P = 0.02), while NAA/Cr ratio was not statistically significant in the lesion of PG ( P = 0.21). Significant metabolic alterations of NAA/Cr and Cho/Cr ratios might be closely related with functional changes of neuropathological process in SN and PG of levodopa treated PD and could be a valuable finding for evaluation of the PD. A trend of NAA/Cr reduction, being statistically significant in older patients, could be indicative of more pronounced neuronal damage in the SN of the progressive PD.

• 한국해양학회지
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• v.26 no.1
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• pp.59-66
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• 1991

Laboratory studies were carried out to measure the sound velocity (V/SUB p/) and quality factor (Q/SUB p/, inverse attenuation) in the horizontal (H) and vertical (V) direction on the core sampled sediment of deep-sea basin (1,850 meter water depth), East Sea of Korea (Sea of Japan). Sampled core was about 250 cm long and 500 kHz ultrasonic p-wave transducer was used for a sound soured. V/SUB p/ varies from 1,480 m/sec to 1,500 m/sec, it is not clear which direction is faster, V/SUB PH/ or V/SUB pv/, within${\pm}$ 1.0% anisotropy (A/SUB p/). It is thought because the core sediment facies is highly (or slightly) bioturbated homogeneous mud with very high porosity (more than 80%). The general trend of Q/SUB p/ is decreasing 10 to 5 with the buried depth, it is strongly affected by the variation of sediment texture (increasing silt, decreasing clay) with increasing of CaCO$_3$ and organic matter content, But Q/SUB PH/ is jumping up to 14.9 near the bottom of core sediment as including volcanic ash richly. The relationship between V/SUB PH/ and Q/SUB PH/ shows the mirror image nearly, it is interpreted that not only the geotechnical properties and texture but also sea-water characteristics (high Q/SUB p/, low V/SUB p/) according to rich water content affect strongly in the upper part of the unconsolidated deep-sea basin sediment.

• Journal of Chest Surgery
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• v.8 no.2
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• pp.149-152
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• 1975

In spite of great advances in surgical treatment during past several decades, surgery of the trachea failed to develop correspondingly, partly because of relative rarity of the tracheal lesions and partly because of difficulties in surgical technique and anesthesia. Surgical diseases of the trachea are largely obstructions due to neoplasm or cicatrical stenosis and tracheal malacia. The present treatment of respiratory failure, using cuffed endotracheal and tracheostomy tubes, has produced, apparently with increasing frequency, tracheal stenosis, tracheomalized tracheal erosion. Surgery is presently the only reasonable way to treat stenotic lesions of the tracheobronchial tree. In the case of tumors, the current trend has been that of radical excision. Primary end-to--end reconstruction of the trachea has been generally recognized as the ideal method of repair following resection. However, for decades it was believed that a maximum of four tracheal rings only might be excised and primary healing achieved with safety. A great variety of procedures, developed by numerous investigations and directed at tracheal substitution, have almost invariably met with discouraging results. A meticulous study done by Grillo and associates on autopsy specimens has shown that an average 6.4cm of mediastinal trachea can be safely resected by full mobilization of the right lung and transplantation of the left main bronchus into the bronchus intermedius. Recently, we experienced a case of successful resection of a tumor of the tracheal carina and primary tracheo-left main bronchial anastomosis at the Department of Thoracic & Cardiovascular Surgery, the National Medical Center in Seoul. The patient, a 29-year-old man, was admitted to the hospital with complaints of dyspnea and cough. On admission, chest film showed hydropneumothorax on the right. After closed thoracostomy, hydropneumothorax disappeared, but hazy densities, developed in the right middle and lower lung fields, resisted to treatment. Bronchoscopy uncovered irregular tumor covering the carina and the right main bronchus, and biopsy indicated well differentiated squamous Cell carcinoma. Operation was performed on July 2, 1975. A right postero-lateral thoracotomy was used. Excision involved the lower trachea, the carina, the left main bronchus and the right lung. This was followed by direct anastomosis between the trachea and the left main bronchus. Bronchography was done on 17th postoperative day revealed good result of operation without stricture at the site ofanastomosis. About one month after the operation symptoms and signs of bronchial irritation with dyspnea developed, and these responded to respiratory care. On 82nd postoperative day, sudden dyspnea developed at night and the patient expired several hours later. Autopsy was not done and the cause of death was uncertain.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.300-305
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• 2002

The construction project is a complex undertaking involving multiple participants. Conflicts are inherently natural in the construction projects and subsequently, a success of projects mainly depends on how well to cope with the conflicts. In the past, courts usually took the position that the professional's exposure in damages for negligent performance of any of his/her duties would not extend to strangers to the contractual arrangement. However, courts today generally reject that rationale which was earlier in vogue and protect architects, engineers, and contractors from being liable to third parties. It means that the lack of privity of contract could rarely protect a profession in a suit alleging the negligence or professional malpractice in preparing plans or specifications. The main goal of this paper is to enhance the understanding of the legal aspect of privity and to provide the trend of no-privity disputes through the analysis of lawsuit cases during the last 40 years. On the base of the analysis, importance of the third relationship and the liability in construction disputes is presented.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.201-208
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• 1994

In order to study the effect of exsisting soil nutritional elements on the nitrogen uptake of sunflower, sorghum and black gram, pot experiment was carried out by using soils sampled from three different depths(0~20, 45~65, 90~110cm) of Brigalow soil in Australia. The results obtained were as follows : Dry matter and nitrogen uptake of corps were increased in the soil with higher nitrogen content. Chlorine uptakes of sunflower and sorghum were increased in the soil with higher nitrogen and lower chlorine contents, but that of black gram was done in the soil with higher contents of both elements. Ratios of nitrogen derived from applied fertilizer of three corps and fixed nitrogen of black gram were relatively low in the soil with higher content of soil nitrogen, but those derived from soil nitrogen were reverse. Recovery rates of applied nitrogen were relatively increased with higher cation uptakes of crops. Chlorine uptakes of sunflower and sorghum were positively correlated with each recovery of nitrogen, but that of black gram didn't show the trend. Recovery rate of applied nitrogen for black gram had significantly negative correlation with increase of soil chloride content.