• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.233-244
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• 2006

Of many volatile organic detergents for metals, benzine(CAS No. 8030-30-6), of which the toxicity has not yet been proven, has been used as an alternative of the halide compounds in the consideration of toxic effects, global warming and the destruction of ozone layer. In order to evaluate the effects of the benzine on human body by investigating the subchronic inhalation toxicity, to obtain the basic data for establishing the criteria of exposure in working environments and to classify the hazardousness in compliance with the Industrial Safety and Health Act by evaluating the hazardousness, repeated inhalation exposure test was carried with SD rats. The rats were grouped by 10 females and males each. The repetitive inhalation exposures were carried out at 4 levels of concentration of 0 ppm, 60 ppm, 300 ppm, and 1,500 ppm, for 6 hours a day, 5 days a week, for 13 weeks. The results are described hereunder. 1. No death of the animals of the exposed and controlled groups in the test period. Not any specific clinical symptoms, change in feed intake quantity, abnormality in eye test, or change in activity were observed. 2. In the 300 ppm and 1,500 ppm groups, weight reduction in the female groups and weight increase of liver and kidney in the male groups compared with control group were observed with statistical significance(p<0.05). 3. In the blood test, the HCT increased in the male 300 ppm group and the number of hematocyte increased, MCV and MCH decreased in the male 1,500 ppm group. In the female 1,500 ppm group, the HB decreased and the distribution width of the hematocyte particle size increased. In the blood biochemistry test, the TP in the male 1,500 ppm group and the LDH in the female 1,500 ppm group were increased with statistical significance(p<0.05). 4. Under the test conditions of the present study with SD rats, the NOEL was evaluated to be from 60 ppm to 300 ppm for both male and female groups. By extrapolation, the NOEL for human who work 8 hours a day was evaluated to be from 128 ppm to 640 ppm 5. Since the NOEL evaluated in this study do not exceed 60ppm(0.184 mg/L) the test material does not belong to the classification of the hazardous substance "NOEL${\leq}$0.5mg/L/6hr/90day(rat), for continuous inhalation of 6hours a day for 90 days" nor to the basic hazardous chemical substance class 1(0.2 mg/L/6hr/90day(rat) defined by the GHS which is a criteria of classification and identification of chemical compounds. However, considering the boiling point($30-204^{\circ}C$), flashing point($-40^{\circ}C$), vapor pressure(40 mmHg), and the inflammable range(1.0 - 6.0 %), sufficient care should be taken for handling in the safety aspects including fire or explosion.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.209-222
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• 1997

Authors surveyed the ground water near the waste disposed from a fiberglass production factory to confirm the presence of glassfiber in the water and to determine the effect of sampling conditions and storage on the recovery of fibrous materials in the ground water. Sample was collected at every 4 hours for 48 hours consecutively. After finishing the 48 hours sample, water sampling was done from each tap after repeated turning on and off the water for 30 seconds at each time. Sample was collected in the two 1.5 liter polyethylene bottle after vigorously shaking the bottle with the same water several times with the flowing tap water. At each paired sample, one bottle was stored stand still at room temperature, and the other sample was filtered immediately after sampling. Water was filtered on the Mixed Cellulose Ester filter with negative pressure. Each sample was divided into upper and lower layer. The other bottle was stored at room temperature standstill for 7 days and filtered in the same fashion as the other pair of sample did. Each MCE filter was divided into 4 pieces and one piece was treated with acetone to make it transparent. Each prepared sample was observed by two researchers under the light and polarizing microscopy, scanning electron microscopy and energy dispersive X-ra microanalysis. Fibers were classified by the morphology and polarizing pattern under the polarizing microscope, and count was done. 1. There was a significant fluctuation in number of the fibers, but there was no specific demonstrable pattern. 2. Non-polarizing fibers frequently disappeared after 7 days's storage. But cluster of fibers were found at the wall of the same container by scratching technique. 3. Polarizing fibers were usually found in between the filter and the manicure pasted area. Possible explanations for this phenomenon will be that either these fibers are very light or have electronic polarity. Hence, these fibers are not able to be attached on the surface of slide glass. 4. Under the scanning electron microscopic examination, the fibers which are not refractive under the light microscopy were identified as glassfiber. Other fibers which is refractive under the polarizing microscopy were identified as magnesium silicate fibers. It is strongly suggested that development of standardized method of sample collection and measurement of fibrous material in the water is needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.181-195
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• 1997

The purpose of this study was to investigate factors affecting the composition and concentrations of fumes generated from various types of welding processes. The results are as follows. 1. Iron(Fe), zinc(Zn) and manganese(Mn) were predominant in Welding fumes. The Fe content in total fumes was 25.5% in coated electrode and 28.2% in $CO_2$ are welding, and the Zn content was 4.5% and 9.1%, respectively, and the Mn was 3.6% and 7.8%, respectively. 2. It was found that the important factors determining composition and concentration of fumes were type of industries, type of welding processes, type and composition of electrodes, composition of base metals, confinement of workplaces or condition of ventilation, work intensity, coated metals such as lead and Zn in paint. 3. The Mn content in airborne fumes was highly correlated with that of electrode(r=0.77, p<0.01) and was about 4 times higher than that in electrodes or base metals. The results lindicate that Mn is well evaporated into air during welding. The higher vapor pressure of Mn may explain this phenomenon. 4. the airborne total fume concentrations were significantly different among types of industries(p<0.001). The airborne total fume concentration was higher in order of sleel-structure manufacturing($GM=15.1mg/m^3$), shipbuilding($GM=13.2mg/m^3$), automobile-component manufacturing ($GM=7.8mg/m^3$) and automobile assembling industry($GM=3.0mg/m^3$) 5. The airbone total fume concentration was 6 times higher in $CO_2$ welding than in coated electrode welding, and approximately 3 times higher in confined area than in open area, in steel-structure manufacturing industry. 6. The concentration of welding fume outside welding helmet was about 2 times higher than that inside it. It is recommened that air sampling be done inside helmet to evaulate worker's exposure accurately, for it has an outstanding effect on reducing worker exposure to fumes and other contaminants.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.751-757
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• 2003

Rapid densification of a SiC-30 wt% TiC powder with additive 10 wt% A1$_2$O$_3$-Y$_2$O$_3$-CaO was conducted by Spark Plasma Sintering(SPS). The fully-densified materials can be obtain through the SPS process with very fast heating rate and short holding time. In the present work, the heating rate and applied pressure were kept to be $100^{\circ}C$/min and 40 MPa, while sintering temperature varied from $1600^{\circ}C$ to $1800^{\circ}C$ for 10 min. The full densification of SiC-30 wt% TiC composites with the addition of $Al_2$O$_3$, $Y_2$O$_3$ and CaO was achieved at the temperature above $1700^{\circ}C$ by spark plasma sintering. The XRD found that 3C-SiC and TiC were maintained the entire SPS process temperature, without phase transformation of SiC and formation of YAG phase to $1800^{\circ}C$. The microstructures of the rapidly densified SiC-30 wt% TiC composites consisted of smaller equiaxed SiC grains and larger TiC grains. The biaxial strength of 635.2 MPa and fracture toughness of 6.12 MPaㆍ$m^{1/2}$ were found for the specimen prepared at $1750^{\circ}C$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.2
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• pp.5-12
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• 2000

Uncooled metallic thin-film thermopile infrared detectors have been fabricated, and the figures of merit for the detectors were examined. The hot junctions of a thermopile were prepared on a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$-membrane which acts as a thermal isolation layer, the cold junctions on the membrane supported with the silicon rim which functions as a heat sink, and Au-black was used as an infrared absorber. Infrared absorbance of Au-black, which strongly depends on the chamber pressure during Au-evaporation and its mass per area, was found to be about 90 ％ in the wavelength range from 3${\mu}{\textrm}{m}$ to 14${\mu}{\textrm}{m}$. Voltage responsivity, noise equivalent power, and specific detectivity of Bi-Sb thermopile infrared detector at 5 Hz-chopping frequency were about 10.5V/W, 2.3 nW/Hz$^{1/2}$, 및 $1.9\times10^{7}$ cm.Hz$^{1/2}$/w at room temperature in air, respectively.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.246-252
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• 2016

Since thermal power plant (TPP) equipment is operated under very high pressure and temperature, failures of the equipment give rise to severe losses of life and property. To prevent the losses, fault detection method is, therefore, absolutely necessary to identify abnormal operating conditions of the equipment in advance. In this paper, we present Mahalanobis distance (MD) based fault detection method for steam boiler tube in TPP. In the MD-based method, it is supposed that abnormal data samples are far away from normal samples. Using multivariate samples collected from normal target system, mean vector and covariance matrix are calculated and threshold value of MD is decided. In a test phase, after calculating the MDs between the mean vector and test samples, alarm signals occur if the MDs exceed the predefined threshold. To demonstrate the performance, a failure case due to boiler tube leakage in 200MW TPP is employed. The experimental results show that the presented method can perform early detection of boiler tube leakage successfully.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1049-1056
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• 2016

The prevalence of diabetes is increasing worldwide, particularly in Asian regions such as Korea. It is estimated that the number of diabetic patients will exceed 5 million by 2030 and that about 30% of people with diabetes are unaware of their condition. A comparative analysis was conducted to determine the relationship between dairy food intake and pre-diabetes risk factors in subjects that visited the health examination center of Sunhan Hospital, Republic of Korea. Subjects were classified into two groups according to fasting blood glucose concentrations: 1) normal (fasting blood glucose <100 mg/dL, n=57) and 2) pre-diabetes (100 mg/dL${\leq}$ fasting blood glucose ${\leq}125mg/dL$, n=56). Total dairy food intake tended to be lower in females and subjects with pre-diabetes compared with males and normal subjects, respectively; however, differences between groups were not significant due to a wide range of variations. HbA1c, systolic and diastolic blood pressures were significantly associated with the prevalence of pre-diabetes. Odds ratios for pre-diabetes were significantly reduced per incremental increases in dairy food intakes after adjusting for confounding factors. Findings in the current study suggest that appropriate intake of dairy foods may need to be considered for the prevention of pre-diabetes.

• Journal of Acupuncture Research
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• v.24 no.1
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• pp.111-125
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• 2007

Objection : The aim of this study was to investigate anti-ischemic effect of LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture. Methods : I designed to investigate whether LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture affects cerebral hemodynamics [regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure (MABP) ] in normal and cerebral ischemia rats by MCA occlusion method, and to make manifest whether LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture is mediated by cyclooxygenase or guanylate cyclase. The changes of rCBF and MABP were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video microscope and width analyzer. Results: The results were as follows ; 1. LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture was significantly increased rCBF, PAD, but decreased MABP after withdrawing of the needle. This results suggest that LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture induced significantly rCBF by dilating PAD. 2. Pretreatment with indomethacin (1mg/kg, i.v.) was significantly inhibited LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture induced increase of rCBF and PAD, but increased LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture induced decrease of MABP after withdrawing of the needle. 3. Pretreatment with methylene blue(10/${\mu}$g/kg, i.v.) was decreased LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture induced increase of rCBF and MABP, but accelerated LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture induced decrease of PAD. This results suggest that the mechanism of LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture is mediated by cyclooxygenase or guanylate cyclase. Conclusion : I suggest that LR1 ${\cdot}$ HT8 ${\cdot}$ HT9 Reinforcement in Acupuncture has an anti-ischemic effect through the improvement of cerebral hemodynamics, and the mechanism IS mediated by cyclooxygenase.

• Journal of Acupuncture Research
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• v.24 no.1
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• pp.1-12
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• 2007

Objectives : Functional dyspepsia is a prevalent disease. It impedes subjective quality of life. The purpose of this research is to examine the effect of acupuncture treatment for functional dyspepsia. Methods : In this randomized, single blind, placebo-controlled study, we compared active acupuncture with sham acupuncture for the treatment of functional dyspepsia. Volunteers who satisfied the requirements were enrolled in study. Severity of dyspepsia was measured by Nepean Dyspepsia Index(NDI) and Functional Dyspepsia Quality fo Life(FD-QOL) before and after treatments. Results : 68 subjects finished study. There were not difference between two groups on age, sex, weight, height, severity of dyspepsia, subtype, Byeonjeung, surmise of treatment. After treatment total key symptoms score, improve rate of key symptoms were decreased than before treatment in active acupuncture group, but there were no statistical significance compared with sham acupuncture group. After treatment "pressure in upper abdomen" and " cramps in upper abdomen" were more decreased in active acupuncture group compared with sham acupuncture group(p=0.001, p=0.014). After treatment total symptom score and QOL of NDI were decreased than before treatment in active acupuncture group, but there were no statistical significance compared with sham acupuncture group. After treatment eating status of FD-QOL in active acupuncture group was significantly increased than sham acupuncture group(p=0.008). After treatment liveliness status of FD-QOL and total score of FDQOL in active acupuncture group was increased than sham acupuncture group though statistically insignificant(p=0.095, p=0.077). Conclusion : Acupuncture treatment is effective to improve the symptoms and quality of life in patients with functional dyspepsia.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.3
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• pp.263-269
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• 2001

Median cleft of the lower lip and/or mandible is a rare congenital anomaly, first mentioned by Couronne in 1819. Monroe(1966), Fujino(1970), Ranta(1984) and Oostrom(1996) conducted comprehensive reviews and list cases in literature. Median cleft varies greatly, from a simple vermilion notch to a complete cleft of the lip involving the tongue, the chin, the mandible, the supporting structures of the median of the neck, and the manubrium sterni. The associated anomalies include ankyloglossia, cleft tongue, neck contraction, heart lesion, absence of hyoid bone, and so on. The etiology of median cleft is unknown. Various possibilities, such as failure of mesodermal penetration into the midline, failure of fusion of mandibular processes, external factors apart from the embryogenic pattern such as pressure, position in utero, circulatory failure caused placental adhesion, diseases in pregnancy, and so on, have been discussed. A 8-year-old girl was referred to the Dept. of Oral & Maxillofacial Surgery, Kyungpook National University Hospital and had been aware of the fact that at birth "she had something wrong with her mouth." Shortly after birth she had been examined by a plastic surgeon and at that time surgical procedure had been performed to release the tongue from the lower jaw and lip at local hospital. On admission, she had a slight notching of lower lip and two fibrous frenum ran from the lip along the ventral surface of the tongue, diastema between her mandibular central incisors, and slightly constricted bifid mandible associated independent movement of the two halves of mandible. The patient had autogenous iliac bone graft to reconstruct the mandibular midline defect. The postoperative result was uneventful. In future, the correction of the soft tissue deformities such as notching of the lower lip and partial ankyloglossia will be required for the esthetic and functional improvement.