• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.253-264
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• 1990

The purpose of this study was to estimate the distribution of absorbed doses of each important organs of head and neck region in panoramic radiography. Radiation dosimetry at internal anatomic sites and skin surfaces of phantom (RT-210 Humanoid Head & Neck Section/sup R/) was performed with lithium fluoride (TLD-100/sup R/) thermoluminescent dosimeters according to change of kilovoltage (65kVp, 75kVp and 85kVp) with 4 miliamperage and 20 second exposure time. The results obtained were as follows; Radiation absorbed doses of internal anatomic sites were presented the highest doses of 1.04 mGy, 1.065 mGy and 2.09 mGy in nasopharynx, relatively high doses of 0.525 mGy, 0.59 mGy and 1.108 mGy in deep lobe of parotid gland, 0.481 mGy, 0.68 mGy and 1.191 mGy in submandibular gland. But there were comparatively low doses of 0.172 mGy and 0.128 mGy in eyes and thyroid gland that absorbed dose was estimated at 85kVp. Radiation absorbed doses of skin surfaces were presented the highest doses of 1. 263 mGy, 1.538 mGy and 2.952 mGy in back side of first cervical vertebra and relatively high doses of 0.267 mGy, 0.401 mGy and 0.481 mGy in parotid gland. But there were comparatively low doses of 0.057 mGy, 0.068 mGy and 0.081 mGy in philtrum and 0.059 mGy in middle portion of chin that absorbed dose was estimated at 85kVp. According to increase of kilovoltage, the radiation absorbed doses were increased 1.1 times when kilovolt age changes from 65kVp to 75kVp and 1.9 times when kilovolt age changes from 75kVp to 85kVp at internal anatomic sites. According to increase of kilovoltage, the radiation absorbed doses were increased 1.3 times when kilovolt age changes from 65kVp to 75kVp and 1.6 times when kilovoltage changes from 75kVp to 85kVp at skin surfaces.

• Journal of dental hygiene science
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• v.9 no.1
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• pp.99-108
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• 2009

The purpose of this study was to investigate the effect of oral health education practice and schoolteacher's self-efficacy on oral health attitude. The data of 217 dental hygienists was subjected to path analysis using AMOS 16.0. Oral health knowledge, attitude, self-efficacy and oral health education practice of schoolteacher were measurement variables of three path models. The goodness of fitness of Knowledge-Attitude-Practice model and Knowledge-Attitude-Self efficacy -Practice model were acceptable. The regression weights of two models were statistically significant. Oral health education practice of schoolteacher gave impact on oral health attitude by mediation of self-efficacy of schoolteacher. Self-efficacy of schoolteacher was a important determinant of oral health education practice. Oral health attitude and practice were supposed to be mutual determinants of health behavior models.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.2
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• pp.59-65
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• 1999

Both the groundwater changes due to different pumping rates and the geochemistry of thermal waters in the Suanbo area are considered in this study. The observation of groundwater level change since 1991 shows that the change is directly correlated with pumping rates of thermal waters and reveals the retardation of ca. 5 weeks after pumping. The hydrogeological aquifer in the area is under reducing condition. The thermal waters are of Na-HCO$_3$ type. and are alkaline (pH=8.5∼8.7) with low TDS values (274∼284 mg/l) and high concentrations of Na (68∼72 mg/l). F (6.4∼8.9 mg/l), and HCO$_3$(136∼146 mg/l). Oxygen and hydrogen isotope ratios of thermal water indicate a meteoric water origin. The activities of Rn-222 and Ra-226 in both thermal water and local groundwater were determined to delineate possible geochemical controls on the Rn-222 and Ra-226. The Rn-222 concentrations are several orders of magnitude greater than the Ra-226 concentrations. The concentrations of Rn-222 range from 190 to 7.490 pCi/1 with an average of 2,522 pCil/l. and those of Ra-226 average 0.32 pCi/1 with the range from 0.25 to 0.42 pCi/1. The concentrations of Rn-222 and Ra-226 are inversely correlated with EC and alkalinity. The pH it positively correlated with Ra-226. The correlation between Rn-222 and Ra-226 is poor. Thermal waters in the study area are produced from highly fractured phyllite. The thermal water qualify. CSAMT (controled-source audiofrequency magnetotelluric) prospecting, and petrological evidences, however, indicate that the heat is possibly transmitted through deep normal faults reaching a deep granite batholith, and the phyllite acts only as a groundwater pathway.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.34-42
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• 2000

Objectives: Periodic limb movements in sleep(PLMS) is a moderately prevalent disorder, of which pathophysiology remains largely unknown. PLMS has been reported to be common in patients with obstructive sleep apnea syndrome(OSAS), but reports on their relationship have been inconsistent in previous studies. Inconsistency of results may be attributable to insufficient number of the study subjects. We attempted to explore the influence of OSAS on PLMS in a large number of subjects. Methods: Three hundred and twenty subjects(M : F=192:128) with PLMS, as identified by the nocturnal polysomnography, were studied. Sample mean age was 53.1(SD=15.1) years and their mean periodic limb movement index(PLMI) is 25.2/hr (SD=24.8). PLMS subjects were divided into two groups, based on the presence or absence of OSAS. Periodic limb movement indices and sleep parameters between two groups were analyzed to evaluate the effects of OSAS on PLMS. Results: Each of PLMI and PLMI with arousal(PLMAI) correlated positively with age. PLMI of men was larger than that of women (p<0.01). The presence of comorbid OSAS independently had influence on PLMI(t=-2.20, p<0.05), but not PLMAI. There were no significant differences between the two groups in their PLMI, PLMAI and sleep parameters. However, the two groups differed in PLMI-correlated sleep parameters. In PLMS subjects with comorbid OSAS, PLMI was negatively correlated with each of slow wave sleep time and REM sleep time. In subjects without comorbid OSAS, PLMI was negatively correlated with sleep efficiency. Conclusion: PLMS patients with OSAS turned out to have increased PLMI than those without OSAS We suggest that OSAS patients may have subtle autonomic arousals and these arousals could, in part, express themselves as PLM.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.107-108
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• 2008

The spectacular development of AMLCDs, been made possible by a-Si:H technology, still faces two major drawbacks due to the intrinsic structure of a-Si:H, namely a low mobility and most important a shift of the transfer characteristics of the TFTs when submitted to bias stress. This has lead to strong research in the crystallization of a-Si:H films by laser and furnace annealing to produce polycrystalline silicon TFTs. While these devices show improved mobility and stability, they suffer from uniformity over large areas and increased cost. In the last decade we have focused on microcrystalline silicon (${\mu}c$-Si:H) for bottom gate TFTs, which can hopefully meet all the requirements for mass production of large area AMOLED displays [1,2]. In this presentation we will focus on the transfer of a deposition process based on the use of $SiF_4$-Ar-$H_2$ mixtures from a small area research laboratory reactor into an industrial gen 1 AKT reactor. We will first discuss on the optimization of the process conditions leading to fully crystallized films without any amorphous incubation layer, suitable for bottom gate TFTS, as well as on the use of plasma diagnostics to increase the deposition rate up to 0.5 nm/s [3]. The use of silicon nanocrystals appears as an elegant way to circumvent the opposite requirements of a high deposition rate and a fully crystallized interface [4]. The optimized process conditions are transferred to large area substrates in an industrial environment, on which some process adjustment was required to reproduce the material properties achieved in the laboratory scale reactor. For optimized process conditions, the homogeneity of the optical and electronic properties of the ${\mu}c$-Si:H films deposited on $300{\times}400\;mm$ substrates was checked by a set of complementary techniques. Spectroscopic ellipsometry, Raman spectroscopy, dark conductivity, time resolved microwave conductivity and hydrogen evolution measurements allowed demonstrating an excellent homogeneity in the structure and transport properties of the films. On the basis of these results, optimized process conditions were applied to TFTs, for which both bottom gate and top gate structures were studied aiming to achieve characteristics suitable for driving AMOLED displays. Results on the homogeneity of the TFT characteristics over the large area substrates and stability will be presented, as well as their application as a backplane for an AMOLED display.

• Journal of Korean Society of Forest Science
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• v.28 no.1
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• pp.1-20
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• 1975

F$\ddot{u}$r die Erforschllng der Variationen bei der Naturpopulationen der Pinus densifiora wurden drei Populationen aus Chuwangsan (Kyong-buk), Anmyondo (Chung-nam) und Odaesan (Kangwon) Ausgewiiblt. Bei je 20 Individuen jeder Population wurden die Variationen von der Eigenschaft der $\ddot{a}$usseren Gestalt, von der anatomischen und morphologischen Eigenschaft der Kiefernadel und von der Holzqualit$\ddot{a}$t an Bohrsp$\ddot{a}$nen untersucht. Das Ergebnis der Untersuchung konnte in den folgenden sechs Punkten formuliert werden. 1. Von den Eigenschaften der $\ddot{a}$usseren Gestalt ist die Geradheit des Baumstamms, der Durchmesser der Zweige und der Winkel der Verzweigung in der Odaesan Population wlinschenswerter als in anderen Populationen. 2. Es wird festgestellt, dass sich die drei Nadelmerkmale, Anzahl der Z$\ddot{a}$hne je 0.5 cm, Anzahl der Stomata-Reihen und Anzahl der Harzkan$\ddot{a}$le, sowohl zwischen den Populationen als auch zwischen den Individuen signignifikant unterscheiden. 3. Bei der Betrachtung des Harzkanal Index, der Schichtanzahl der Hypodermis und der Entfernung der Fibrovasalb$\ddot{u}$ndel wird aufgezeigt, dass sich alle drei gepr$\ddot{u}$ften Populationen geringf$\ddot{u}$gig von der normalen Kiefer unterscheiden. 4. Zwischen den Populationen ergibt sich ein Unterschied im Prozentanteil des Spatho lzes und im spezifischen Geswicht, jedoch zeigt die Breite der Jahresrings und die Tracheidenl$\ddot{a}$nge keinen Unterschied. Das spezifische Gewicht und die Tracheidenl$\ddot{a}$nge der Individuen jeder Population ist signifikant verschieden. 5. Bei dem Alter 11-20 ist der Prozentanteil des sp$\ddot{a}$tholzes am gr$\ddot{o}$ssten und wird aber danach immer geringer bis zum Alter 30; sp$\ddot{a}$ter zeigt sich dann keine sichtbare Ver$\ddot{a}$nderung mehr. Das spezifische Gewicht sich vergr$\ddot{o}$ssert bei der Zunahme des Jahresrings, nimmt aber dann in Anmyondo und Odaesan Populationen beim Alter 21-30 wieder ab. Die Tracheidenl$\ddot{a}$nge der drei Populationen besitzen die Neigung, sich nach der zunahme der Jahresringe zu vermehren. 6. Mit diesen hier behandelten Charakteren werden ganz allgemeinen die Unterschiede der drei Kiefer populationen festgestellt. Diese Ergebnisse sind sehr bemerkenswert betrachtet vom genetischen Gesichtspunkt der waldbaumpopulation.

• Journal of Korean Academy of Nursing
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• v.24 no.4
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• pp.545-556
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• 1994

Medical insurance and health care delivery system enabled Korean people to get the necessary medical service, but it caused increased needs for medical service, and resulted in the occurence of some problems such as a lack of manpower and medical facilities. In order to solve these problems, many countries, which already had medical insurance system had developed home care system and it has been regarded effective both in reducing costs and in increasing the rates of turnover of bed. Recently, Korea has included home nursing care in its health care delivery system, and some models of the hospital based home nursing care had been tried and its effects had been evaluated. So, author tried to run a home nursing care for the Cesarean section mothers and evaluate Its effects both in the mother's health and costs. This study was designed as a Quasi-experimental study. Subjects were thirty mothers who got Cesarean section operation in hospital in Seoul. Experimental group consisted of 15 volunteers, and control group were selected by means of matching technique. Data were gathered from February 1st to March 26th by two assistants who were trained by author. Experimental group were discharged on the 4th day after their operation, and got nursing care and assessment about their home three times on the 5th, 6th, and 7th day. Control group stayed in the hospital until 7th day as usual and were checked on the same day as above mentioned To evaluate the state of physiological recovery, vital signs, H.O.F, presence of edema in the legs, bathing, appetite, sleep, presence of pain or discomfort in the breasts, amount of lochia, color of lochia, defecation urination. To compare incidence of complication in experimental group with that in control group, specific assessment was done such variables as smell of lochia, presence of inflammation of operation wound, dizziness, and presence of immobilization in the extremities. The activities of daily living were checked Satisfaction of nursing were checked To calculate costs, author asked subjects to specify expenditure including hospital charge, traffic enpenses, and food expenses. The results were as fellows. 1. On effectiveness of home nursing careThere were n significant differences between experimental and control group in incidence of abnormal symptoms and any complication. The number of taking a bath [POD #5 P=0.001, #6 P=0.0003, #7 P=0.001] and the degree of appetite [POD #5 P=0.03, #6 P=0.02, #7 P=0.013] were significantly higher in experimental group than in control group. Contrary to author's expectation, the degree of the activities of daily living in experimental group was not higher than that of control group. All of the experimental group said they were satisfied with the home nursing care. 2. Cost analysis 1) Hospital charge of experimental group was lower than that of control group. ［P=0.009］ By taking home nursing care, average period of hospitalization was shortened to 3.1 days, and family members could save 22.8 hours. Total amount of money saved by early discharge was 3,443,093 Won. It is estimated that total amount of money saved by early discharge in a year will be 40,398,956 Won. 2) Home nursing care charge of 15 mothers was 1,781,633 Won. It is estimated that total amount of money Saved by it in a year Will be 20,904,493 Won. It was lower altogether than hospital charge of the three days which is 5th, 6th, 7th day of operation. The average cost of single home visit was calculated 10,940 Won. It took 87 minutes per round and it costed 1,017.3 Won. The average hour of home care was 39.0 minutes. 3) It is expected that early discharge can bring forth the increase of hospital income. On the condition that the rate of running bed is 100%, the expected increase of hospital income will be 202,374, 026 Won in a year. Suggestions for further study and nursing practice are as follows : 1. For the welfare of patients and the increased rates of running bed, home nursing care system should be included in the hospital nursing care system. 2. Studies to test effect of home nursing care on the patients with other diseases are needed. 3. Establishment of law on the practice of home nursing care is strongly recommended.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.436-442
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• 2017

Fischer-Tropsch synthesis is the technology of converting a syngas (CO+$H_2$) derived from such as coal, natural gas and biomass into a hydrocarbon using a catalyst. The catalyst used in the Fischer-Tropsch synthesis consists of active metal, promoter and support. The types of these components and composition affect the reaction activity and product selectivity. In this study, we manufactured an iron catalyst using ${\gamma}-Al_2O_3/SiO_2$ mixed support (100/0 wt%, 75/25 wt%, 50/50 wt%, 25/75 wt%, 0/100 wt%) by an impregnation method to investigate how the composition of ${\gamma}-Al_2O_3/SiO_2$ mixed support effects on the reaction activity and product selectivity. The physical properties of catalyst were analyzed by $N_2$ physical adsorption and X-Ray diffraction method. The Fischer-Tropsch synthesis was conducted at $300^{\circ}C$, 20bar in a fixed bed reactor for 60h. According to the results of the $N_2$ physical adsorption analysis, the BET surface area decreases as the composition of ${\gamma}-Al_2O_3$ decreases, and the pore volume and pore average diameter increase as the composition of ${\gamma}-Al_2O_3$ decreases except for the composition of ${\gamma}-Al_2O_3/SiO_2$ of 50/50 wt%. By the results of the X-Ray diffraction analysis, the particle size of ${\alpha}-Fe_2O_3$ decreases as the composition of ${\gamma}-Al_2O_3$ decreases. As a result of the Fischer-Tropsch synthesis, the CO conversion decreases as the composition of ${\gamma}-Al_2O_3$ decreases, and the selectivity of C1-C4 decreases until the composition of ${\gamma}-Al_2O_3$ was 25 wt%. In contrast, the selectivity of C5+ increases until the composition of ${\gamma}-Al_2O_3$ is 25 wt%.

• Tuberculosis and Respiratory Diseases
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• v.51 no.4
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• pp.354-363
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• 2001

Background : Although lung involvement has been reported in 5 to 46% of dermatomyositis/polymyositis(DM/PM) patients, reports of the condition in Korea are rare. This study evaluated the clinical features of lung involvement in DM/PM patients. Methods : The medical records, laboratory results and radiologic findings of 79 DM/pM patients, who attended the Seoul National University Hospital (SNUH) between 1989 and 1999, were reviewed retrospectively. Results : A total 79 patients of whom 24 patients(33%) showed lung involvement, were enrolled in this study. More patients with lung involvement were female(F:M=11:1), and older compared with those without lung involvement. Patients with lung involvement presented with dyspnea(79%), coughing(67%), an elevated ESR, and CK/LD. Anti-Jo 1 antibody test was positive in 30%, which is significantly higher in patients with lung involvement. A simple chest X-ray of the patients with lung involvement exhibited reticular opacity(50%), reticulonodular opacity(30%), patchy opacity(29%), nodular opacity(13%) and linear opacity(4%). HRCT(n=24) showed ground glass opacity(75%), linear or septal thickening(50%), patchy consolidation(42%), honey-combing(33%) and nodular opacity(17%). The pulmonary function test showed a restrictive ventilatory pattern(77%) and a lower diffusing capacity(62%). The patients were followed up during a mean duration of $30{\pm}28$ months. They were treated with steroid only(50%) or a combination of steroids and cytotoxic agents(46%). Muscle symptoms were improved in 89% with treatment, but an improvement in the respiratory symptoms or in the pulmonary function test was rare. Patients with lung involvement had a higher mortality rate(21%) than those without lung involvement(10%) during the follow-up periods. Conclusion : DM/PM patients with lung involvement were mostly female, older and had a higher positive rate Anti-Jo 1 antibodies, but there was no significant difference in prognosis.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.618-627
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• 1999

Background : Rifampicin (RFP) is a key component of the antituberculous short-course chemotherapy. Usually the RFP resistant M.tuberculosis is also resistant to isoniazid (INH), so the RFP resistance is the marker of multi-drug resistant (MDR) tuberculosis. But unusual cases of mono-RFP-resistant tuberculosis have been recently reported with increasing frequency, especially associated with HIV infection in western countries. Therefore, we conducted a retrospective study to investigate the frequency, causes, and the clinical characteristics of mono-RFP-resistant tuberculosis in Korea. Methods : Of the bacteriologically confirmed and susceptibility-proven 699 pulmonary tuberculosis patients (921 isolates) who visited Asan Medical Center from January 1990 to August 1997, eighteen patients with INH-susceptible and RFP-resistant tuberculosis were evaluated. Previous history of tuberculosis, antituberculous drug compliances, associated systemic illness, drug susceptibility patterns, and clinical outcomes were analysed. And rpoB gene sequencing was done in 6 clinical isolates of M. tuberculosis. Results : The mean age of 18 patients was $43{\pm}14$ years, and the sex ratio is 12:6 (M : F). Sixteen (89%) patients had previous history of tuberculosis. None had diagnosed gastrointestinal disorders, and 2 HIV tests that were performed came out negative. Susceptibility tests were done repeatedly in eleven patients, and six (55%) were mono-RFP resistant repeatedly while five (45%) evolved to MDR tuberculosis. Eight (44%) patients were cured, six (33%) failed, three (17%) were lost to follow-up, and the other one is now on treatment. rpoB gene sequencing showed 5 mutations, codon 531 TCG to TIG mutation in 4 isolates and 526 CAC to TAC in 1 isolate. Conclusion : The clinical characteristics of mono-RFP resistant tuberculosis were similar to that of MDR tuberculosis in Korea where the HIV infection rate is lower than western countries. But some patients with mono-RFP-resistant tuberculous could be cured by primary drug regimens including RFP, suggesting that mono-RFP-resistant tuberculous is a different entity from MDR tuberculosis.